SPELEX – Ensuring Electromagnetic Harmony Inside Your Electronics.

Ensuring Electromagnetic Harmony Inside Your Electronics.

Help to identify and fix EMI/EMC design problems.

EMC design review during the design phase.

Reducing interference and restoring Signal/Power Integrity.

Matching input(S11) and output(S22) impedance of a

Matching input(S11) and output(S22) impedance of a narrow band RF Power Amplifier.
The bottom display shows the transfer characteristic(S21).
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#spelex
#electronicengineer #electronicdesign
#rf #rfdesign #vna #vectornetworkanalyzer
#rfamplifier #amplifier #poweramplifier
#sparameter

The project is an RF SDR tranceiver (Software Defi

The project is an RF SDR tranceiver (Software Defined Radio).
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The RF design consist of:
- Digital RF Attenuator
- 7order RF Low Pass Filter
- RF Low Noise Amplifier
- Differential RF Anti-Aliasing Filter
- ADC 16bits/105MSPS (LTC2217)
- Bus Driver - 16bits
- DAC 14bits - 275MSPS (DAC5672)
- Reconstraction RF LPF
- RF Power Amplifier
- Low Jitter VCXO 100MHz
- Low Noise Voltage regulators
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The digital board is an EVB from Terasic DE1-SOC with the Intel FPGA
Cyclone V.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign #altium
#altiumdesigner #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard

This is an assembled RF power preamplifier circuit

This is an assembled RF power preamplifier circuit board built with lumped components.
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#spelex
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign #rf
#rfdesign #analogdevices #we #würthelektronik
#rfamplifier #printedcircuitboard

This is an Evaluation Board of a Linear-in-dB VGA

This is an Evaluation Board of a Linear-in-dB VGA with AGC Detector, that works up to 500MHz.
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#spelex #agc #vga #ad #analogelectronics #analogdevices #rf #amplifier #sma #ad8367

Near Field vs. Far Field Measurements. In the ne

Near Field vs. Far Field Measurements.

In the near field wave impedance depends on the nature of the source and the distance from it. In the far field the impedance is constant.

We can see from the pictures that in the near field region fields can range from predominantly magnetic to predominantly electric wave impedance. Near field measurements are used for EMI/EMC troubleshooting, since they allow one to pinpoint sources of energy and they may be performed without the need for a special test site.

However compliance testing is performed in the far field and predicting far field energy levels from near field measurements can be complicated because the strength of the far field signal is dependent not only on the strength of the source, but also the radiating mechanism as well as any shielding or filtering that may be in place.

As a rule of thumb we must remember that we if are able to observe a signal in the far field then we should be able to see the same signal in the near field. However it is possible to observe a signal in the near field and not see the same in the far field.

The pictures from MPS presentation.
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#spelex #emcconsulting
#emcconcept #emcdesigner #emitroubleshooting
#emc #emv #emi #electromagneticcompatibility
#hefield #nearfield #farfield
#mps #tektronix

With the help of these photos, I would like to hig

With the help of these photos, I would like to highlight the various EMI / EMC design methods that helped the developer create a low noise precision electronics and go through the necessary EMC tests.

Look at PCB layout at specific locations, component placement, and functional grouping on the board.

These are fotos of the Analog Output Module APAX-5028 from #Advantech company.

This high-precision (14 bit) module is used in industrial automation and, of course, complies with EMC - CE and FCC Class A certifications.
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#spelex #emi #emc
#emitroubleshooting
#electromagneticcompatibility
#emcconsulting #industrialcontrol
#pcb #printedcircuitboard
#automation #filter #emifilter
#commonmodechokes

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Computer Module of a Vending Machine.

DESCRIPTION OF THE PROBLEM:
The pre-compliance test for EMI Radiated Emission failed by around 6-8 dB in the 120 MHz range.

SOURCE OF THE PROBLEM:
There was a signal integrity problem of the high speed interfaces which caused the EMI problem.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting
#highspeedsignal

This is a one of explanations of where to place ES

This is a one of explanations of where to place ESD diodes to protect the external interfaces of electronic devices from electrostatic discharge (ESD).

ESD protection is designed not only to protect your device from damage, but also to ensure that the device operates at its nominal operating mode in ESD conditions. Therefore, there are various types of protection as Hardware(SCH and PCB) as well as Software.

Many of them can be detected and prevented during an EMC/EMI design review, at an early stage of development.

Brief summary as a rule of thumb:
Place ESD elements as close to external connectors as possible.

Of course, this is not a full answer of ESD protection, just a start point...

I took this interesting picture from a ESD book or research paper that I saw on internet.

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#spelex #emcconsulting
#emcconcept #emi #emv #emc
#esd #esdprotection #emitroubleshooting #pcb #sch

Ground Bouncing is a form of noise that occurs dur

Ground Bouncing is a form of noise that occurs during digital switching when component/die grounds on the PCB are at different voltages.

Ground bounce may also disturb digital signals with a very low clock frequency, e.g., 50 kHz as in the picture. The problem is the very quick digital outputs of #MCU / #FPGA, which have a wide bandwidth. The voltage from the top picture drops by 840mv, that disterb the signal integrity of the digital #SPI signal.

On the bottom picture is a repaired communication between the MCU/FPGA and #DAC.

Ground Bouncing problem can be solved by slowing down the digital signals and careful design grounding concept in the system.
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#spelex #emcconsulting
#emcconcept #emitroubleshooting #pcb #pcbdesign
#digitalelectronics
#emc #emv #emi #electromagneticcompatibility
#grounding #groundingconcept #signalIntegrity #powerintegrity #groundbounce

Ettus USRP N210 inside - SDR transceiver. . . . #s

Ettus USRP N210 inside - SDR transceiver.
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#spelex #sdr #pcb #rf #fpga #ettus #usrp

These are interesting experiments, that explains h

These are interesting experiments, that explains how many GND vias need to be placed around vias that carry differential signal when changing PCB layers.

There are no pure differential signals in our real world and any practical differential signals also contains a certain part of common mode signal.
When a common signal passes in the signal vias the currents flow in the vias in the same direction and have an identical amplitude. The electromagnetic fields that the vias radiate interfere with fields of the differential signal and radiation losses of the target signal might be grater than in case of pure differential signal.

You can see from the pictures, that losses less than 5% for the following cases (rule of thumb):
Up to 5 GHz, without any GND vias
Up to 30 GHz, with 2 GND vias.
Up to 35 GHz, with 6 GND vias.
Up to 50 GHz, with 8 GND vias.

(GND vias are the vias that placed around the vias with differential signals)

I got this information from the latest issue of the Signal Integrity online magazine. (Signal Integrity Journal)
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#spelex #emi #emc
#emitroubleshooting
#emcconsulting #lvds
#pcb #differentialsignals #printedcircuitboard #via
#signalintegrity #signalintegrityjournal
#highspeedcircuit #highspeedsignal
#highspeeddata

This is a Linux(LXDE) launch of my Software Define

This is a Linux(LXDE) launch of my Software Defined Radio (SDR) project. Before the launch is shown the process of programming the bridge between FPGA and ARM Cortex-A9 (SoC Cyclone V). The FPGA is used because the video decoder chip (VGA) is connected to the FPGA pins instead of the ARM.

This operation system will be used to run FFT anlysis application and display a spectrum and a waterfall of the received signal.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign #altium
#altiumdesigner #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard #lxde #linux #vga #fft

These are fotos of the Analog Output Module APAX-5

These are fotos of the Analog Output Module APAX-5028 from #Advantech company.

This high-precision (14 bit) module is used in industrial automation and, of course, complies with EMC - CE and FCC Class A certifications.

See how it's designed...
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#spelex #emi #emc
#emitroubleshooting
#electromagneticcompatibility
#emcconsulting
#pcb #printedcircuitboard
#automation

This is a quick check, if an RF chain with an #ADC

This is a quick check, if an RF chain with an #ADC work. Namely, that the ADC sees filtered and amplified signal.

The performance test will be done in the lab, but after the fist start, during commitioning, it is good to know that modules at least work.

It is necessary to check this functionality without connecting to a digital board and programming an FPGA.

The external #oscillator generate a signal, that I couple with a help of my hand to an RF input. The blue LED is a part of the circuit that catches and hold overflow events of an ADC on the board.
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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#radioelectronics
#analogelectronics #digitalelectronics #sdr
#rf
#analogfrontend
#electronicmeasurement #led #leds

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
NFC-B (RFID) Communication.

DESCRIPTION OF THE PROBLEM:
The pre-compliance EMV test failed. The device did not receive the NFC test signal from the distance specified in the standard.

SOURCE OF THE PROBLEM:
The TX channel worked fine.The RX channel was not sensitive enough due to non-optimized connections (Antenna-RX-TX).
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting
#highspeedsignal #nfc #antenna #tx

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
High Precision Industrial PID Controller.

DESCRIPTION OF THE PROBLEM:
Problem measuring the accuracy of analogue signals (PT100, PT1000).

SOURCE OF THE PROBLEM:
An EMC issue on the board. Noise spikes caused by inadequate filtering of the DC/DC converter. This disturbed a low noise Analogue to Digital converter (ADC - 21 bits). A second problem was related to the grounding concept.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting
#highspeedsignal #dcdc
#adc #noise #groundingconcept
#groundbounce
#groundloop

The signal integrity (SI) of the JTAG interface is

The signal integrity (SI) of the JTAG interface is just as important as that of other high speed interfaces.

The photo shows a self-made JTAG adapter cable, which was made without due consideration the integrity of the signal. Worst of all, the PCB was also designed with no regard for the signal integrity of the JTAG interface. The idea was that JTAG has a low clock frwquency and that signal integrity is not worth paying attention to.

Some roughting errors on the #PCB and ill-conceived adapter cable led to the fact that the FPGA was not programmed.

This JTAG connection was used to program Flash based #FPGA (Microsemi). The programmer (FlashPro4) generates a 4 MHz clock signal by default, but can be reduces to 1 MHz.

The FPGA programming software installed on the PC is so smart that it identified the Signal Integrity Problem and reported it to the developer.
(See picture)

Reducing the JTAG clock frequency to 1 MHz only helped to hide 🙂 the message about the signal integrity problem. The FPGA was not properly programmed and the tool showed a problem during the FPGA check. (See picture)

At the end, the problem was identified and solved.
In the next posts, I will show what was the error on the PCB.
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#spelex #emi #emc
#emitroubleshooting
#electromagneticcompatibility
#emcconsulting
#cable #jtag #si
#signalintegrity

Variable Noise Filter is a very useful and quite r

Variable Noise Filter is a very useful and quite rare feature of an oscilloscope.

I am wonder that, the budget version of the mixed signal oscilloscope from Textronix MSO2024B has this feature - Noise Filter/Glitch filter. This option allows directing the input signal through a lowpass filter that can be adjusted from 6 kHz to 200 MHz band.

As a result, the signal in the desired frequency bandwidth looks good readable and excellent for reports.
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#spelex #emcconsulting
#emcconcept #emitroubleshooting
#emc #emv #emi #electromagneticcompatibility
#noise #filter #tektronix #oscilloscope #measurements #lowpass #glitch

Electronics designers face the choice of electroni

Electronics designers face the choice of electronic components every day. One of the most popular types of components are capacitors. There are many different types of capacitors on a market. It is important for a good developer to stay afloat and not drown out from a large number of types. Understanding the important parameters allows you to create a reliable and cost-effective device. Prices for some types of capacitors can vary hundreds or more times.

This picture compares the ESR between different types of capacitors. You can see that there are two types of aluminum capacitors (electrolytic and polymer) whose ESR varies hundreds of times at room temperature. Visually, they are very similar with slight differences in labeling.

An engineer, if he is not sure, can choose the most expensive capacitor and think he is on the safe side.

This is exactly the case I encountered while troubleshooting EMC self-compatibility. An LDO was oscillating in one performance sensitiv project that I described in my previous posts.

Informative images are taken from a Wurth Electronic presentation.
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#spelex #emitroubleshooting #emi #emc #capacitors #esr #electromagneticcompatibility
#we #würthelektronik #aluminiumpolymer
#aluminiumelectrolytic

One of the PCB layout concepts of a mixed signal b

One of the PCB layout concepts of a mixed signal board.

In the photos, the possible placement with the separation of digital and analog circuits. And possible common-mode power filter between them.

The photos are taken from a book: PCB design techniques for EMC compliance.
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#spelex #emcconcept #emitroubleshooting #pcb #pcbdesign
#digitalelectronics #analogelectronics
#emc #emv #emi #electromagneticcompatibility
#grounding #groundingconcept #groundbouncing

It is always useful when a ground on a PCB is bein

It is always useful when a ground on a PCB is being split to leave the option to combine it with 0 ohm resistors or stitching capacitors.

In this case you can check if the ground was splitted correctly or if they need to be merged.

This trick allows to reduce risks and avoid of redesigning the PCB.
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#spelex #emcconsulting
#emcconcept #emitroubleshooting #pcb #pcbdesign
#digitalelectronics
#emc #emv #emi #electromagneticcompatibility
#grounding #groundingconcept #groundbouncing

I have finished refurbishing of the linear power s

I have finished refurbishing of the linear power supply (5v/1A), that I will use to power analog RF front end. This is an old power supply was made by #AIWA in Japan. I have installed an additional voltage regulator, which acts as a good ripple filter. This is a famous #LM317, that has an excellent ripple rejection ratio of more than 60db at 100 Herz. As I showed in my previous post, the ripples at the output of the initial voltage regulator were 150mV (1A/7V). This is to much for the sensitive electronics. #spelex #powersupply #linearpower #hardware

I have build this RF adapter to compensate gain ch

I have build this RF adapter to compensate gain changes over frequency in a wideband RF amplifier.
The whole chain is used for amplification of a high speed digital (Baseband) signal in an RF communication system.

An RF chain with three RF amplifiers from #Minicircuits has a total gain around
45 dB in bandwidth 10MHz - 2000MHz, but the amplification changes around 12dB.

The present adapter consist of RC filter and reduces gain variation over frequency from 12dB to 2.0dB. This changes allow to have a quiet constant amplitude of the digital signal for required data rate.
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#spelex #rf #smaadapter #sma #amplifier #gaincompensation

The frequency-phase detector is a part of the PLL

The frequency-phase detector is a part of the PLL and was implemented using Intel primitives inside the FPGA (Cyclone V).

In the simplest case, the role of such a detector can be performed by the "exclusive OR" element. However, the simplest phase detectors have a significant drawback - with a phase shift close to zero, their transfer coefficient decreases, and a "dead zone" appears on the transfer characteristic.

A more advanced phase detector is free from this shortcoming, which, in particular, is available as a separate AD9901 IC.

I tested this #VHDL code together with the external low jitter #VCXO 100MHz and the reference oscillator 50MHz. The PLL stabilized sidnal clock preasice ADC and DAC.

This PLL will be used in my Software Defined Radio (SDR) hobby project.
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#spelex #electronicsprojects
#altiumdesigner #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur #pll

Side view on the PCB. ------------------‐-------

Side view on the PCB.
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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #sdr
#würthelektronik #rf
#shielding #analogfrontend #texasinstruments

This is an RF load + Attenuator from Minicircuits.

This is an RF load + Attenuator from Minicircuits.

BW-N20W20+

RF load - 20W, DC-18 GHz
RF Attenuator - 20 dB
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#spelex #emcconsulting
#emitroubleshooting #rf #attenuator #load #radioelectronics
#analogelectronics
#rfdesign #microwave #rfengineering
#emc #emv #electromagneticcompatibility
#minicircuits

On way of connecting Source electrode of the Power

On way of connecting Source electrode of the Power GaAs FET to the Ground in the RF Power Amplifier.
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#spelex
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign #rf
#rfdesign #analogdevices #we #gaasfet
#rfamplifier #printedcircuitboard #amplifier #poweramplifier

These are simulated LVDS signals that are carried

These are simulated LVDS signals that are carried along the printed circuit board. The signal integrity simulation is done in the Hyperlynx program from Mentor. The simulations are not include a PCB influence, that will also change the quality of the differential traces.

I have used for these simulations a worst-case LVDS driver skew scenario 0.3-0.5ns, for different PCB trace length.
As a result of this violation the signal integrity of high-speed signals can be damaged. The skew can also be affected by the symmetry of the differential traces, which can be broken by the distance to the differential traces.

There is also another problem of broken symmetry, an increased level of electromagnetic interference. This was a part of EMC analysis to eliminate electromagnetic interference in a system.
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#spelex #emi #emc
#emitroubleshooting
#emcconsulting #lvds
#hyperlynx #pcb
#signalintegrity #ti
#simulation #emcconcept

This is a method to reduce the conducted emissions

This is a method to reduce the conducted emissions (EMI) from the DC/DC converter to the RF circuit.

An RF amplifier built with JFET transistors requires a negative bias voltage at the gate electrode.
Very often this voltage is generated by a DC/DC converter. Which generate a wide range of electromagnetic interference and can interfere with the target signal.

A moat in the ground plane around a DC/DC converter directs the converters ground current away from other components.

In general, this is a very good electronics design rule, and can be applied to more than just RF circuits.

The picture is from the book:
"Essentials of RF and Microwave Grounding"
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting
#electronicengineer
#circuitboard #pcb #pcbdesign #rf
#rfdesign #rfamplifier #printedcircuitboard

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Entertainment System ( #Automotive )

DESCRIPTION OF THE PROBLEM:
A high-speed digital interface on the board had a communication problem. The #PCB was carefully designed with signal integrity in mind. The layout of the high-speed signals on the PCB was developed using a simulation tool.

SOURCE OF THE PROBLEM:
Power Integrity Issue on the board. Noise on the power rail of the #CPU shifts the threshold of high-speed communication ( #FPGA + CPU + #Memory ), thereby compromising the integrity of the High-Speed Signal ( #SI ) on the PCB.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting #signalintegrity
#powerintegrity
#pdn #powerdistributionnetwork

This is an RF power pre amplifier circuit board bu

This is an RF power pre amplifier circuit board built with lumped components.
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#spelex
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign #rf
#rfdesign #analogdevices #we #würthelektronik
#rfamplifier #printedcircuitboard

The project is an RF Analog Front End, that can be

The project is an RF Analog Front End, that can be used for different purposes, for example SDR (Software Defined Radio).
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The design consist of:
- Digital RF Attenuator
- 7order RF Low Pass Filter
- RF Low Noise Amplifier
- Differential RF Anti-Aliasing Filter
- ADC 16bits/105MSPS (LTC2217)
- Bus Driver - 16bits
- DAC 14bits - 275MSPS (DAC5672)
- Reconstraction RF LPF
- RF Power Amplifier
- Low Jitter VCXO 100MHz
- Low Noise Voltage regulators
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign #altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur

This is a protected printed circuit board using pl

This is a protected printed circuit board using plexiglass cut on a CNC machine.(see my previous posts)

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #sdr
#rf

In this video, I demonstrated how incorrect timing

In this video, I demonstrated how incorrect timing constraints will sound in an FPGA design. The test was conducted during the development of a software-defined radio (SDR).

At the beginning of this video, I showed the fading effect of short wave propagation (without timing violation) just to get an idea of what it sounds like and how it differs from the timing violation problem in the FPGA.

Then I blew on the fpga and recorded the sound as the temperature changed fast.

At the end, I showed how the system behaves when the room temperature is slowly changing.
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#spelex #fpga #Intel #terasic #radioelectronics #de1soc #cyclone #analogelectronics #digitalelectronics #receiver #sdr #hamradio #vhdl #verilog #timingconstraints

How many decoupling capacitors around an #FPGA or

How many decoupling capacitors around an #FPGA or an #MCU do we need? It is not easy to say.

Design of a power distribution network (Power Integrity) is a separate big topic in modern electronics design.

And, without analysing, simulation and measurement of the #PDN, we are just playing in "Russian Roulette" with our design (Henry Ott wrote in his EMC book.)

And many years later, a huge number of companies continue to spend big money on redesigning and retesting boards that did not work reliably.
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#spelex #emcconsulting
#digitalelectronics
#emc #emv #emi #electromagneticcompatibility #powerdistributionnetwork
#powerintegrity
#pcb #pcbdesign

How can we calculate a total power consumption and

How can we calculate a total power consumption and efficiency during electronic design phase? How can we warn about the overload of some power components?

There are many different possibilities that begin from paper and pen, Excel table and up to special development tool.

I almost always use Excel tablets, but I have found another tool that can help in system power design of any projects, especially if there are many different voltages.

This is LT Power Planner tool from Analog Devices. it is an interesting and visual tool that is easy to use. It can be used regardless of the component manufacturers, but it can be more useful in a detailed analysis if you use chips from AD.
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#spelex #analogdevices #lineartechnology #ltpowerplanner #electricaldesign #digitalelectronics #analogelectronics

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Home Automation Controller (Smart House)

DESCRIPTION OF THE PROBLEM:
The pre-compliance test for EMI Radiated Emission failed.

SOURCE OF THE PROBLEM:
Signal Integrity problem on the PCB. Incorrect routing of digital signals when traversing PCB layers.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting #smarthouse

Ferrite bead is a passive frequency dependent resi

Tesla Autopilot HW2.5 and Infotainment Boards. Lo

Tesla Autopilot HW2.5 and Infotainment Boards.
Looks amazing and very professional!!!

I wonder if the PCB developers, judging by the photos of the boards, use separate grounds...

The pictures were taken from the:
https://www.flickr.com/photos/jurvetson/50938493268/in/photostream
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#spelex #emcconsulting
#emcconcept #emitroubleshooting #pcb #pcbdesign #printedcircuitboard
#digitalelectronics
#emc #emv #emi #electromagneticcompatibility
#grounding #groundingconcept #signalIntegrity #powerintegrity #groundbouncing #tesla
#teslamodel3

This is an amazing free simulation tool: QUCS (Qui

This is an amazing free simulation tool: QUCS (Quite Universal Circuit Simulator)

It is able to simulate not only Spice models, but also S-parameters.

I have checked different Free RF simulators, but didn't find a Stability simulation. QUCS can do this and many other interesting analysis.

I started using it during the development of the RF Power Amplifier.

I will check during prototyping if it simulates correctly.
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#spelex #rf #rfamplifier #simulation
#qucs #sparameters

Line Impedance Stabilisation Network (LISN). . . .

Line Impedance Stabilisation Network (LISN).
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#spelex #emcconsulting
#emcconcept #emitroubleshooting #pcb #pcbdesign
#emc #emv #emi #electromagneticcompatibility
#grounding
#lisn #lineimpedancestabilizationnetwork

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Vibration Analysis and Multi-Channel Data Acquisition Systems (Measurement of Turbines, Motors, Gearboxes)

DESCRIPTION OF THE PROBLEM:
The system wasn’t stable. The FPGA on the board sometimes received incorrect data from memory. This was especially noticeable in the upper part of the address range, data from lower address ranges were received correctly.

SOURCE OF THE PROBLEM:
Signal Integrity problem, which caused the EMI problem. Adjacent high-speed signals interfere with each other, resulting in crosstalk and in turn selection of the wrong address.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept #fpga
#electromagneticcompatibility
#emitroubleshooting #sdram #sram #acquisitionsystem

Installed TFT Displays on DE1-SoC (FPGA +ARM) Deve

Installed TFT Displays on DE1-SoC (FPGA +ARM) Development Kit.
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#spelex #electronicsengineering #electronicdesign
#circuitboard #digitalelectronics #highspeedcircuit
#fpga #altera #cyclone #intel #terasic
#tft #tftdisplay

A very interesting new solution from Murata... An

A very interesting new solution from Murata...

An L Cancel Transformer (LCT) is a component that greatly suppresses noise in high-frequency bands by reducing the ESL generated inside capacitors and the ESL generated in boards when used together with a decoupling capacitor. The L Cancel Transformer (LCT) is outstandingly effective in suppressing harmonic noise of several MHz to 1 GHz in power lines caused by DC-DC converters and other components.

An L Cancel Capacitor (LCT) can improve the noise elimination performance of decoupling capacitors. Accordingly, noise suppression becomes possible with a smaller number of MLCCs. It also becomes possible to cut the number of small-capacity MLCCs and other components to reduce harmonic noise.
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#spelex
#murata
#powersupply
#powerintegrity
#pdn #powerdistributionnetwork
#emc #emi #emv #electromagneticcompatibility
#emitroubleshooting
#lowpassfilter #damping #dcdcconverter

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
NFC-A (RFID) Communication.

DESCRIPTION OF THE PROBLEM:
The pre-compliance EMV test failed. The transmitted NFC waveform had overshoots and is not following the standard.

SOURCE OF THE PROBLEM:
Impedance matching problem between the antenna and the #RF amplifier.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting
#rfid #nfc

Assembled Wilkilson RF power splitter/combiner bas

Assembled Wilkilson RF power splitter/combiner based on lumped components.
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#spelex
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign #rf
#rfdesign #analogdevices #we #würthelektronik
#wilkinson

This is a measurement of a LVDS signal generated b

This is a measurement of a LVDS signal generated by SN65LVDS1 (630-Mbps) driver. The driver is connected to a LVDS receiver at a distance of about 25cm.

The signal has no signal integrity problem, but there are oscillations that occur due to the SKEW between differential signal + PCB (non-uniformity of board fibers). This oscillations can cause EMI problems at 500MHz.

In case of a short differential PCB trace(less 7cm), these oscillations can be overlapped with reflections from the LVDS receiver. These type of combination change the quality of the rising edge of the pulse. Some rising edge sensitive applications will have signal integrity issues that are detected during these measurements (EMI troubleshooting).
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#spelex #emi #emc
#emitroubleshooting
#emcconsulting #lvds #ti
#measurements #oscilloscope #tektronix

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.

PROJECT:
Instrumental Electronic Device of a Space System (Spacecraft)

DESCRIPTION OF THE PROBLEM:
A very weak analogue signal from the instrument contains unwanted noise and spikes in the specified frequency range. The system worked better on battery power. Filters on the power rails were implemented.

SOURCE OF THE PROBLEM:
The Switching Mode Power Supply (SMPS) generates strong high-frequency EMI surges that need to be suppressed. Measurements and analysis showed that generated EMI passed through a filter that is transparent at those frequencies. The power system needed optimization to deliver power without noise.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting
#switchmodepowersupply #smps

This are measurements of an LVDS signal with diffe

This are measurements of an LVDS signal with different type of oscilloscope probes. The signal is measured at a load side with 100ohm resistor. Between an LVDS driver and the load are #PCB traces, connector, cable and another connector.
On the top side of the picture is a measurement with a help of single ended probes, on the bottom side with a differential probe #tpd1000. There is also a strong (in the form of a jump in amplitude) reflection caused by the impedance mismatch.
The differential probe measurement is a very useful to check the signal integrity, but not always suitable for EMI measurement. The single active probe measurement can help to find source of EMI.

This is part of the tests (EMI troubleshooting) to eliminate electromagnetic interference related to emission and immunity.
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#spelex #emi #emc
#emitroubleshooting
#emcconsulting #lvds
#measurements #oscilloscope #tektronix #signalintegrity

The optical quadrature encoder has also a bouncing

The optical quadrature encoder has also a bouncing problem. The digital debouncer filter was used to solve this problem. I tested my #VHDL code, which will be used in my Software Defined Radio (SDR) hobby project.
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#spelex #electronicsprojects
#bouncing #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver #dimming #opticalencoder #vhdl
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur

3D View is a nice option of the Altium Designer. I

3D View is a nice option of the Altium Designer. I like it.

The project is an RF Analog Front End, that can be used for different purposes, for example SDR (Software Defined Radio).
------------‐----------------------------
The design consist of:
- Digital RF Attenuator
- 7order RF Low Pass Filter
- RF Low Noise Amplifier
- Differential RF Anti-Aliasing Filter
- ADC 16bits/105MSPS (LTC2217)
- Bus Driver - 16bits
- DAC 14bits - 275MSPS (DAC5672)
- Reconstraction RF LPF
- RF Power Amplifier
- Low Jitter VCXO 100MHz
- Low Noise Voltage regulators
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#circuitdesign #altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur #3d

The photo shows some changes on the PCB of the RF

The photo shows some changes on the PCB of the RF amplifier to reduce the quality factor (de-Q) of the RF Choke (RFC). These changes will ensure the stability and performance of the RF amplifier.

Some low-pass or Bias-T filters that built with high quality components (low R inductor and low ESR capacitor) and at some ratio between their values will have a resonant frequency. At these unwanted resonant frequencies, the low pass filter has a resonant spike and can act as a bandpass filter.

The de-Q procedure helps to dampen the filter, which has been implicitly formed from the inductor and decoupling capacitors. When designing filters or RF chokes, the self-resonant frequencies (SRF) of the coils as well as LC damping must be taken into account.

The second and third figures show the transfer functions (S21) of the RF amplifier without and with damping elements of the bias-t, that I have measured with a help of a VNA.
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#spelex #emcconsulting
#emcconcept #emitroubleshooting #pcb #pcbdesign #rfc #rf #choke
#qfactor #filter #resonans #measurement
#agilent #vna

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.

The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Instrument Electronics of a Space System (Spacecraft)

DESCRIPTION OF THE PROBLEM:
The electronic module generated a high level of Common-Mode (CM) Conducted Emissions (CE) at the primary power side of the DC/DC converter.

SOURCE OF THE PROBLEM:
Unwanted current spikes occured during nominal system operation. The generated EMI propagated through the system and appeared on the primary input lines. The primary side of the DC/DC converter requires optimization (filtering).
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept #emi #filter
#electromagneticcompatibility
#emitroubleshooting

These are ceramic and tantal capacitors under #FPG

These are ceramic and tantal capacitors under #FPGA on the printed circuit boardsof the Ettus USRP N210 SDR transceiver.

The ceramic capacitors are placed as close as possible to the power pins of the FPGA, and tantalum capacitors are placed a little further.

The capacitors are parts of the power distribution network (#pdn) to create a necessary over frequency impedance at power pins.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign
#radioelectronics
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard #ettus #usrp

What's inside Mini Circuits RF Bias-Tee? ZFBT-4R2

What's inside Mini Circuits RF Bias-Tee?

ZFBT-4R2GW+
0.1MHz-4200MHz
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#spelex #rfdesign #hardware #electronicdesign #electronicdesign #circuitboard #pcb #pcbdesign
#circuitdesign #minicircuits
#analogelectronics #sma
#rf #biastee #ferrite #balun #coils

Have you ever used Ethernet interface without any

Have you ever used Ethernet interface without any transformers?

In some special applications, isolation transformer can be a critical component that must be avoided.

It is good that TI has already analyzed this solution, that is described in an application note.

This method can be used in any configurations like:
Capacitor-Cable-Capacitor
Transformer-Cable-Capacitor
Capacitor-#PCB-Capacitor

The validation results presented in this application shows that is able to work in a
transformerless configuration in 10MB and 100MB with error-free operation up to a 120-meter CAT-5 cable.

This transformer less, simple solution has no common mode EMI filter that is included in many ethernet interfaces. Therefore, it can cause EMI problems during EMC test.
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#spelex #emcconsulting
#emi #emitroubleshooting
#ti #ethernet #emc #texasinstruments #transformerless

Switching on SDR for the first time (MW and SW). T

Switching on SDR for the first time (MW and SW). To begin with, I implemented the simplest direct demodulation of AM and SSB signals without IQ channels. The video shows only the reception of AM signals. Instead of an antenna, a heating system in a multi-story building was used.
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#spelex #electronicsprojects #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #hamradio #radioamateur #vhdl

This is a useful graph that allows you to quickly

This is a useful graph that allows you to quickly determine what frequency different logic element families can emit.

I use it during EMI troubleshooting and EMC design review, to find potential sources of EMI.

It is always better to choose the slowest component in terms of EMI.

The pictures are from #TI and #toshiba application notes
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#spelex #emcconsulting #emcconcept #emi #emc #electromagneticcompatibility #emv #emitroubleshooting
#digitalelectronics

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Industrial Controller.

DESCRIPTION OF THE PROBLEM:
The pre-compliance test for EMI Radiated Emission failed.

SOURCE OF THE PROBLEM:
Signal Integrity problem, which caused the EMI problem. Insufficiently thought out the #PCB design of the High-Speed Ethernet controller and ground.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept #radiatedemission
#electromagneticcompatibility
#emitroubleshooting
#ethetnet #industrialcontrol
#highspeedsignal

Reduced phase noise (jitter) of a PLL. . . . #spel

Reduced phase noise (jitter) of a PLL.
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#spelex #emcconcept #emitroubleshooting
#analogelectronics #emc #emv #emi #electromagneticcompatibility #pll #measurements
#jitter #oscilloscope

These are the RF Up-Converter and Down-Converter P

These are the RF Up-Converter and Down-Converter PCBs of the Ettus USRP SDR transceiver.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign
#radioelectronics
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard #ettus #usrp

These are the printed circuit boards of the Ettus

These are the printed circuit boards of the Ettus USRP N210 SDR transceiver.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign
#radioelectronics
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard #ettus #usrp

This is a 4-Port SuperSpeed Isolated USB 3.0 Hub w

This is a 4-Port SuperSpeed Isolated USB 3.0 Hub with up to 5 Gbps transfer speed USB-4630 from Advantech.

It was purchased for ground isolation during space electronics testing in the lab.

Separate DC/DC converter of the minicomputer generated an EMC with a electrical fast transient (EFT) every 5-10 minutes. A fast transient signal propagated across the PCB and the microcontroller hung up. This case exposed the weaknesses in the design (EFT Immunity).

The USB isolator shown allowed further testing and analysis of the EMC problem without stopping the project.

It was interesting to see how it was possible to realize such a high data rate with galvanic isolation. As you can see from the pictures, capacitive coupling is implemented here.
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#spelex #emi #emc
#emitroubleshooting #pcb #usb
#systemdesing #advantech
#grounging #eft #usbhub
#groundingconcept

In one of my previous posts, I showed a JTAG inter

In one of my previous posts, I showed a JTAG interface signal integrity problem that happened in one project. The JTAG interface just stopped working after the board was redesigned.

The reason was crosstalk between the JTAG interface tracks on the PCB. The pictures show traces from the both PCB and calculated values of their cross coupled signals.

Crosstalk is a result of the unintentional coupling of electromagnetic fields and causes both forward and reverse reflections. The easiest way to reduce crosstalk from a nearby aggressor signal is by:
- increasing the spacing between the signals.
- reducing the distance between the signal trace to reference plane.

A good rule of thumb for this is gap = 3*trace width.
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#spelex #electronicsengineering #emcconsulting
#emcconcept #electronicdesign #emitroubleshooting #pcb #pcbdesign
#analogelectronics #printedcircuitboard
#emc #emv #emi #electromagneticcompatibility
#grounding #signalIntegrity #crosstalk #jtag

This is an evaluation board of an ADS1282 High-Res

This is an evaluation board of an ADS1282 High-Resolution Delta-Sigma ADC (124-dB SNR (1000 SPS)). The datasheet says the resolution can be up to 32 bits.

The ADS1282 is an extremely
analog-to-digital high-performance, single-chip converter(ADC) with an integrated, low-noise programmable gain amplifier (PGA) and two-channel
input multiplexer (MUX).

I have measured a noise flor of the chip on the evaluation board ~130dbFS.
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#spelex #emi #emc
#emitroubleshooting
#pcb #sigmadelta
#ti #adc #pga #dsp
#systemdesing

Locking the phase lock loop (PLL) from my previous

Locking the phase lock loop (PLL) from my previous posts.

The #VHDL code will be used in my Software Defined Radio (SDR) hobby project.
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#spelex #altera
#fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics
#rfdesign #sdr #hamradio #radioamateur #pll #vcxo

Wilkilson RF power splitter/combiner based on lump

Wilkilson RF power splitter/combiner based on lumped components.
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#spelex
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign #rf
#rfdesign #analogdevices #we #würthelektronik
#wilkinson

There are different types of noise distribution th

There are different types of noise distribution that can be statistically measured with the help of an oscilloscope. A few of them, the most popular, are shown in the picture.

This information can help to find a source of the problem during EMC/EMI debugging in a very low noise system.

The picture was taken from one of Teledyne webinars.

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#spelex #electronicmeasurement
#lownoisedesign #emc #emv #noise #emi
#signalintegrity #powerintegrity
#analogelectronics #digitalelectronics
#rfdesign #highspeedcircuit #teledyne #oscilloscope

The VCXO on my PCB works and can be received by a

The VCXO on my PCB works and can be received by a supported SDR Play receiver.

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign #circuitboard #pcb #pcbdesign #radioelectronics
#analogelectronics #digitalelectronics #sdr
#rf #analogfrontend #sdrplay
#electronicmeasurement #vcxo

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Security System.

DESCRIPTION OF THE PROBLEM:
Incorrect operation of the system due to „magic” disturbances related to the weather. The system was in the production phase. The requirement was to learn from the issues in the current release, implementing fixes and increasing quality in the subsequent release.

SOURCE OF THE PROBLEM:
Incorrect system behaviour due to problems with ESD Immunity at input/output signals.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting

When the comparator's hysteresis is small and chan

When the comparator's hysteresis is small and changes with a temperature variation.
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#spelex #emi #emc #emv
#emitroubleshooting #measurements
#oscilloscope #comparator

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.

PROJECT:
Tiny IoT Device

DESCRIPTION OF THE PROBLEM:
The device was intermittent and did not consistently work as expected. This was visible when people moved near the device.

SOURCE OF THE PROBLEM:
ESD Immunity was poor. Moving people generate electrostatic discharge that causes unwanted disturbances (level upset) in the unprotected circuit.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept #groundingconcept
#electromagneticcompatibility
#emitroubleshooting #grounding
#highspeedsignal #iot #esd #emc #electromagneticcompatibility
#emv

The correct concept of grounding in a system or on

The correct concept of grounding in a system or on a printed circuit board (PCB) is quite a challenge.

Ground splitting is a tradeoff between achieving system performance, a level of complexity and levels of Emission and Immunity (EMC).

Whether you are designing your electronics with a solid ground or a split ground, it is important to understand where the main and return current flows (in the range - from DC to RF).

Very oft, it is almost impossible to change the location of interface/backplane connectors, power components, etc. These reason push the developer to think about splitting ground plane.

I can say about my experince:
* For a simple, low power, PCB with MCU and 8-10bits ADC + display normally you don't need the GND splitting. (Home automation, simple IoT, etc.)
* Solid/Splitting ground must be carefully designed for mixed signal electronics with digital, low noise analog, and DC/DC components. (Space electronics, IoT with RF, high-precise instrumental electronics, RF software defined radio - SDR). For Power electronics with analog readout and DSP shaping system. (Power drivers and inverters).

Complex reliable electronics like Space/Automitive/Defence requared very deep worst case analisys (WCA). In turn, it become very difficult to achieve requirements without splitting the ground.

Proper ground separation and placements of stitching capacitors helped me to reduce interference (EMI) by 60 dB. These disturbances reduced significantly the LIDAR system performance. The electromagnetic interference was originated from the FPGA interconnect and affected the low noise laser drivers. As a result of the EMI reduction, the laser line width(phase noise) was significantly reduced to the requared system level. The Radiation Emission level after the changes were also complient with the EMC standards.

Here are some my photos from tests and measurements of the device after making changes to the PCB.
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#spelex #emcconsulting
#emcconcept #emitroubleshooting #pcb #pcbdesign
#analogelectronics
#emc #emv #emi #electromagneticcompatibility
#grounding #groundloop #groundingconcept #signalIntegrity #powerintegrity

@wedontknowzipcodes
@juanmicuesta96

Near Field Emissions H-Field Scan of Tight vs. Loo

Near Field Emissions H-Field Scan of Tight vs. Loose Coupling for differential signals (LVDS, USB, ETHERNET etc.)

The picture is from an application note - Gentex Corporation.
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#spelex #electronicsengineering #emcconsulting
#emcconcept #electronicdesign #emitroubleshooting #pcb #pcbdesign
#analogelectronics #printedcircuitboard
#emc #emv #emi #electromagneticcompatibility
#grounding #groundingconcepts #signalIntegrity #powerintegrity #lvds #usb #ethernet #differentialsignal #rfsimulation #field #nearfield #differentialpair #emission #gentex

Power Distribution Network (PDN) of an ASIC. . .

Power Distribution Network (PDN) of an ASIC.
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#spelex #emcconsulting
#digitalelectronics
#emc #emv #emi #electromagneticcompatibility #powerdistributionnetwork
#powerintegrity #pdn #asic
#pcb #pcbdesign #capacitors #tantalum #polymer

A new EMI/EMC task has been resolved. The list wit

A new EMI/EMC task has been resolved.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Instrumental Electronic Device of a Space System (Spacecraft)

DESCRIPTION OF THE PROBLEM:
Development of a grounding concept diagram that describes deliberate grounding separation, minimization of ground loops and reduction of the generation of EMI between modules. This diagram also includes analogue and digital signal groups, shows potential collisions and suggests ways to mitigate potential interference.

SOURCE OF THE PROBLEM:
The system was investigated, potential risks were identified and analyzed, and ways to prevent EMC disharmony were proposed. As a result, the concept of the grounding architecture was developed and a detailed report was drawn up.
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#spelex
#emc #emv #emi #emcconsulting #emcconcept #electromagneticcompatibility
#emitroubleshooting
#groundingconzept
#groundloops

This is a mathematical modulation / demodulation m

This is a mathematical modulation / demodulation model for the RF SDR (Software Defined Radio) transceiver from my previous posts.

I took an audio file with a pleasant "I don't understand" female voice, modulated this signal using AM-DSB and AM-SSB modulation (IQ signals), and then upconverted it to a few MHz.

The received signal was then downconverted (IQ signals) and demodulated with a different frequency offset.

This mathematical algorithm will be implemented in an #FPGA.
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#spelex
#radioelectronics
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver #sdr #hamradio #radioamateur
#softwaredefinedradio
#matlab #ssb #dsb #am

The project is an RF SDR tranceiver (Software Defi

The project is an RF SDR tranceiver (Software Defined Radio).
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The RF design consist of:
- Digital RF Attenuator
- 7order RF Low Pass Filter
- RF Low Noise Amplifier
- Differential RF Anti-Aliasing Filter
- ADC 16bits/105MSPS (LTC2217)
- Bus Driver - 16bits
- DAC 14bits - 275MSPS (DAC5672)
- Reconstraction RF LPF
- RF Power Amplifier
- Low Jitter VCXO 100MHz
- Low Noise Voltage regulators
‐-----------------------------------------
The digital board is an EVB from Terasic DE1-SOC with the Intel FPGA
Cyclone V.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign #altium
#altiumdesigner #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard

Breadboard (PCB) testing at -45°C. This is a cabl

Breadboard (PCB) testing at -45°C. This is a cable hole with some air leakage that has formed ice due to condensation.
The thermal chamber has a compressed air tube connected to avoid condensation inside.
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#spelex #emcconsulting
#emcconcept #emitroubleshooting #hardwaretest #thermal #condensation
#thermalchamber #ice #cable

The controller of a Numerical Control Oscillator (

The controller of a Numerical Control Oscillator (NCO) is designed. It allows the setting of the frequency in the binary format 28 bits using an optical encoder and two buttons. The buttons can be used to change the encoder step. (1KHz, 100KHz and 1MHz) The set frequency is then decoded to a decimal format to display it. The first two digits of the 7 Segments are the megahertz range.

The LEDs below the digits are the implementation of the logarithmic RSSI indicator with some test values. The input of the RSSI is connected to the output of the NCO only for test purposes.

I tested my #VHDL code, which will be used in my Software Defined Radio (SDR) hobby project.
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#spelex #electronicsprojects
#altiumdesigner #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver #pwm #dimming #7segment
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur #nco

This is a good example of how DC/DC converters are

This is a good example of how DC/DC converters are laid out on a PCB.
I hope the ground plates under the converters are also separated by islands.

These DC/DC converters are on the printed circuit boardsof the Ettus USRP N210 SDR transceiver.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign
#radioelectronics
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard #ettus #usrp

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Tiny Tracker System (IoT).

DESCRIPTION OF THE PROBLEM:
The device did not receive a stable GNSS signal. An evaluation board with such a chip and antenna works quite well.

SOURCE OF THE PROBLEM:
The sensitivity of the GNSS (GPS) receiver was significantly reduced due to common grounding issues between the GNSS module, the LNA, the MCU, the DC/DC converter and the RF transceiver.

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#spelex
#emc #emv #emi #emcconsulting
#emcconcept #groundingconcept
#electromagneticcompatibility
#emitroubleshooting #grounding
#highspeedsignal #fr #gnss #gps #mcu #lna #tracker #iot

The phase lock loop (PLL) for the external low jit

The phase lock loop (PLL) for the external low jitter VCXO 100MHz was implemented (see my previous post) and tested.
The PLL was designed using VHDL primitives on FPGA Cyclon V from Intel (Altera).

4 LEDs show the locking sequence. They connected to the same 4 lock detection modules, but with different locking time.

Multimeter is connected at the point where the output of the loop filter is connected to the VCXO. At the end of the video is visible that the VCXO input is very sensitive to the different disturbances. The wire of the multimeter works as an antenna and it breaks the stabilization of the PLL.

The #VHDL code will be used in my Software Defined Radio (SDR) hobby project.
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#spelex #altera
#fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics
#rfdesign #sdr #hamradio #radioamateur #pll #vcxo

Narrowband PLL behavior after blowing on VCXO. Dig

Narrowband PLL behavior after blowing on VCXO.
Digital XOR PLL is implemented in FPGA with a passive RC loop filter. VCXO is CVHD-950X-100.000MHz

This is a part of the Software Defined Radio (SDR).
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#spelex #emcconcept #emitroubleshooting
#analogelectronics #emc #emv #emi #electromagneticcompatibility #pll #measurements
#jitter #oscilloscope #FPGA #vcxo #vco #crystek #sdr

This figure shows various ways to practically and

This figure shows various ways to practically and quickly match the impedances of the RF components on the manufactured PCB.

Taken from a book "Microwave hybrid amplifier realization"
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#spelex
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign #rf
#rfdesign #analogdevices
#rfcircuits #printedcircuitboard #impedancematching #microstrip

These are useful pictures that explain how electri

These are useful pictures that explain how electric return current flows at different frequencies (1KHz, 50KHz, 1MHz).

The current returns to the source through the least impedance path. The impedance value depends on the frequency. So the return current can flow into the absolutely different directions on the PCB.

As a result, critical signals can be corrupted by electromagnetic interference (EMI) and EMC problems can occur in the system.

Therefore, when designing or reviewing a PCB, try to think about the possible return current paths for each signal.

The pictures are from Design Tips 2008.
Bruce Archambeault
Resistive vs. Inductive Return Current Paths
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#spelex #electronicsengineering #emcconsulting
#emcconcept #electronicdesign #emitroubleshooting #pcb #pcbdesign
#analogelectronics #printedcircuitboard
#emc #emv #emi #digitalelectronics #electromagneticcompatibility
#grounding #groundingconcepts #signalIntegrity #powerintegrity #returncurrentpath

This is a side view of my latest PCB. The project

This is a side view of my latest PCB.

The project is an RF Analog Front End, that can be used for different purposes, for example SDR (Software Defined Radio).
------------‐----------------------------
The design consist of:
- Digital RF Attenuator
- 7order RF Low Pass Filter
- RF Low Noise Amplifier
- Differential RF Anti-Aliasing Filter
- ADC 16bits/105MSPS (LTC2217)
- Bus Driver - 16bits
- DAC 14bits - 275MSPS (DAC5672)
- Reconstraction RF LPF
- RF Power Amplifier
- Low Jitter VCXO 100MHz
- Low Noise Voltage regulators
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign #altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur

This is an RF power amplifier circuit board built

This is an RF power amplifier circuit board built with lumped components.
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#spelex
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign #rf
#rfdesign #analogdevices #we #würthelektronik
#rfamplifier #printedcircuitboard

This is an example of dimming 7-segment LED indica

This is an example of dimming 7-segment LED indicators using PWM. I tested my #VHDL code, which will be used in my Software Defined Radio (SDR) hobby project.
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#spelex #electronicsprojects
#altiumdesigner #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver #pwm #dimming #7segment
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur

This interesting PCB simulation video shows how cl

This interesting PCB simulation video shows how close placed vias to differential high speed traces can affect other traces (crosstalk).

There is a 3W rule of thumb for high-speed differential signals like LVDS and other. Follow this rule, without any simulations, the signal integrity will not eliminate signal integrity and EMI from these traces will be minimal.

I have seen, during EMI troubleshooting, many digital PCB designs without following this rule of thumb. The signal integrity was fine, up to some frequencies (data rate) and the devices were working fine in a wide temperature range. The LVDS is a pretty reliable interface, which can forgive many errors.

Breaking the symmetry of an LVDS trace due to not following a rule of thumb, creates reflections, changes the skew between P and N in a differential trace, and generates EMI.

But these generated EMI will be detected only during EMC tests, that is too late. And new PCB design spin will be started... spending money...

I took this video from the Simbeor YouTube channel. (Crosstalk between differential strips and vias)
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#spelex #emi #emc
#emitroubleshooting
#emcconsulting #lvds
#simbeor

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.

PROJECT:
Smart Metering with Sigfox (IoT).

DESCRIPTION OF THE PROBLEM:
The receiver on the breadboard wasn’t sensitive enough. It didn’t receive all messages transmitted. The evaluation board worked well and the RF connections and antenna were developed by RF experts.

SOURCE OF THE PROBLEM:
The switching power supply emits high near-field and conductive RF noise. This noise disturbs the EMC harmony on the board and reduces the performance of the RF Sigfox chip.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept #groundingconcept
#electromagneticcompatibility
#emitroubleshooting #grounding
#highspeedsignal #fr #sigfox

Any clocked interfaces are a source of potential e

Any clocked interfaces are a source of potential electromagnetic interference (EMI). The EMC problem may not arise if all circuit and PCB design rules are followed.

If it is not possible to make a redesign, it is possible to reduce the level of interference by turning off clock of SPI interface.
This can be done if it doesn't need frequently update the parameters of the connected SPI devices.

I designed SPI Master driver, where I can select between the burst mode and update mode.

Burst mode - clock is enabled and sending always the data to MOSI.

Update mode - the clock and MOSI will be active only if the previous sent data is different to the actual.

This SPI diver was developed using the VHDL language for FPGAs in my hobby project Software Defined Radio (SDR).

Real tests of the EMI levels (for the two SPI modes) and their impact on the received and demodulated signal will be shown in the following posts.
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#spelex #emi #emc #emv #electromagneticcompatibility #electronicsprojects #fpga #radioelectronics #analogelectronics #digitalelectronics #trx #tranceiver #receiver #spi #vhdl #sdr #hamradio #radioamateur #modelsim

This is an example of a cable ground and shield co

This is an example of a cable ground and shield connection between external devices with LVDS signals.

These methods should be used to reduce radiated electromagnetic interference (EMI) and increase the susceptibility (Immunity) of the system.

In fact, just one resistor/capacitor can greatly reduce EMI, prevent ground loop, make the system work and save time.
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#spelex #emi #emc
#emitroubleshooting
#emcconsulting #lvds
#signalintegrity #gnd #groundingconcepts
#shielding #cable
#groundloop
#resistor #capacitor

This figure shows what to do with the ground plane

This figure shows what to do with the ground plane under the #DC blocking capacitors in the #high-speed interface circuit.

The plane underneath the pads of DC blocking capacitors should be removed, as highlighted in the
following figure, to match the impedance of the pad and maintain signal integrity.

The picture is from the RTG4 #FPGA Datasheet (#Microsemi / #Microchip)
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#spelex #emcconcept #emitroubleshooting #pcb #pcbdesign #digitalelectronics #digitalelectronics #electronics #emc #emv #emi #electromagneticcompatibility #grounding #groundingconcept #groundbouncing #signalintegrity

This is an image from #analogdevices that shows th

This is an image from #analogdevices that shows the relative noise level generated by different switching power supply topologies.
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#spelex #emcconsulting
#emcconcept #emitroubleshooting
#analogelectronics
#emc #emv #emi #electromagneticcompatibility
#grounding #buckboost #dcdc

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
Smart House System.

DESCRIPTION OF THE PROBLEM:
Poor voice quality when making a phone call or a voice command.

SOURCE OF THE PROBLEM:
An internal EMC problem due to the emission of digital signals causing interference to on the audio intercom system.
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#spelex
#emc #emv #emi #emcconsulting
#emcconcept
#electromagneticcompatibility
#emitroubleshooting

This is an evaluation board of an LMK04832 Ultra L

This is an evaluation board of an LMK04832 Ultra Low-Noise JESD204B Compliant Clock Jitter Cleaner With Dual Loop PLLs.

The choice of suitable elements for the generation and distribution of clock signals is one of the main tasks in the development of system design.

The capabilities of this chip allow to generate clean clock signals for sensitive elements of the RF system, such as FPGAs, high-speed ADCs / DACs.
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#spelex #emi #emc
#emitroubleshooting
#emcconsulting #lvds
#pcb #clock #jitter
#clockdistributor
#ti #JESD204B #pll
#systemdesing

What's inside Mini Circuits RF Bias-Tee? ZFBT-282

What's inside Mini Circuits RF Bias-Tee?

ZFBT-282-1.5A+
10MHz-2800MHz
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#spelex #rfdesign #hardware #electronicdesign #electronicdesign #circuitboard #pcb #pcbdesign
#circuitdesign #minicircuits
#analogelectronics #sma
#rf #biastee #ferrite #balun #coils

The project is an RF SDR tranceiver (Software Defi

The project is an RF SDR tranceiver (Software Defined Radio).
------------‐----------------------------
The RF design consist of:
- Digital RF Attenuator
- 7order RF Low Pass Filter
- RF Low Noise Amplifier
- Differential RF Anti-Aliasing Filter
- ADC 16bits/105MSPS (LTC2217)
- Bus Driver - 16bits
- DAC 14bits - 275MSPS (DAC5672)
- Reconstraction RF LPF
- RF Power Amplifier
- Low Jitter VCXO 100MHz
- Low Noise Voltage regulators
‐-----------------------------------------
The digital board is an EVB from Terasic DE1-SOC with the Intel FPGA
Cyclone V.
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#spelex #electronicsprojects
#circuitboard #pcb #pcbdesign #altium
#altiumdesigner #fpga #Intel #terasic
#radioelectronics #de1soc #cyclone
#analogelectronics #digitalelectronics #rf #trx #tranceiver #receiver
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur
#printedcircuitboard

This is an example of protecting the analog output

This is an example of protecting the analog outputs of industrial controllers.
The circuit has EMC, ESD, overvoltage and fault voltage tollerance protection.

The example taken from #texasinstruments application note.
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#spelex #emi #emc
#emitroubleshooting
#electromagneticcompatibility
#emcconsulting #electricalprotection
#industrialdesign #tvs #esd
#automation #industrialcontroller #fault

This is a fine tuning process with a VNA help of t

This is a fine tuning process with a VNA help of the RF filter from my previous posts. The external variable capacitors allows to perform tuning.
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#spelex #electronicsengineering #electronicsprojects #hardware
#electronicengineer #electronicdesign
#radioelectronics
#analogelectronics
#rfdesign #rf
#filter #coilcraft #lpf #harwin
#vna #vectornetworkanalyser
#emi #emitroubleshooting
#electronicmeasurements

This is an assambled Low Pass Filter without of a

This is an assambled Low Pass Filter without of a nice metal can.

On the board is an elliptical LPF 7 order. The adjacent coils are places at 90 degree to reduce a coupling effect.

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#spelex #electronicsengineering #electronicsprojects #hardware
#electronicengineer #electronicdesign
#radioelectronics
#analogelectronics
#rfdesign #rf
#filter #coilcraft #lpf #harwin

These are already tuned low pass filters for the R

These are already tuned low pass filters for the RF Analog Front End from my previous posts.
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#spelex #electronicsengineering #electronicsprojects #hardware
#electronicengineer #electronicdesign
#radioelectronics
#analogelectronics
#rfdesign #rf
#filter #coilcraft #harwin

This is a Line Impedance Stabilisation Network (LI

This is a Line Impedance Stabilisation Network (LISN) from TEKBOX.
It helps to troubleshoot conductive emmitions up to 30MHz.
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#spelex #emcconsulting
#emcconcept #emctest
#emitroubleshooting #emi
#tekbox #lisn

A new EMI/EMC issue has been resolved during EMI t

A new EMI/EMC issue has been resolved during EMI troubleshooting.
The list with typical resolved EMI/EMC problems is on the website: www.spelex-i.com

PROJECT:
High-Frequency Digital Communication System (RF – QAM64)

DESCRIPTION OF THE PROBLEM:
Some electronics on the PCB generated distortions, which then generated spectral regrowth, adjacent channel interference and a deterioration of the Error Vector Magnitude (EVM) performance.

SOURCE OF THE PROBLEM:
There was a Power Integrity issue on the PCB. Ground bounce on the digital signals modulated the intermediate frequency signal. As a result, additional distortions in the RF channel degraded the quality of the digital signal demodulation.
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#spelex
#emc #emv #emi #evm #electromagneticcompatibility
#emitroubleshooting
#qam #communicationsystem
#powerintegrity #rfchannel #pcb #printedcircuitboard #groundbounce #rf #highfrequency #highspeedcircuit

Just found breadboards of my old project, that I d

Just found breadboards of my old project, that I did 15 years ago.
This was a portable shortwave cw transceiver for 7MHz, 10MHz and 14MHz. There were analog receiver and transmitter, with a digital control from a microcontroller Atmega16.
Also, I have used a DDS synthesizer AD9834 to generate RF signals. On the board you can see a crystal intermediate frequency filter, that consists of 4 quarts with a frequency 4.19MHz.
On the board are also visible bistable relays, that switch the filters. Bistable relays was a good decision for a battery powered device.
A C code of the MCU, I tested in a interesting software - Ptoteus with visual debugging.
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#circuitdesign #altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #hamradio #radioamateur #shortwave
#breadboard #cw #mcu
#atmel

The PCB is soldered. I conduct a visual inspection

The PCB is soldered. I conduct a visual inspection.

On this photo is a LowPass Filter and an RF transformer (Balun).

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#circuitdesign #altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #sdr #balun
#würthelektronik
#microstrip #differentialsignal

Checking at home with SDR Play if the #VCXO is gen

Checking at home with SDR Play if the #VCXO is generating a signal 100MHz. This is a low jitter clock signal for the ADC and DAC.

This VCXO will be stabilized with a digital #PLL that will be implemented in the FPGA.

Then, a phase noise of the stabilized VCXO could be measured using a spectrum analyzer.

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#analogelectronics #digitalelectronics #sdr
#rf #sdrplay
#analogfrontend
#electronicmeasurement

This is a 3D View of the board with metal cans, wh

This is a 3D View of the board with metal cans, which shield the critical RF circuits.

The project is an RF Analog Front End, that can be used for different purposes, for example SDR (Software Defined Radio).
------------‐----------------------------
The design consist of:
- Digital RF Attenuator
- 7order RF Low Pass Filter
- RF Low Noise Amplifier
- Differential RF Anti-Aliasing Filter
- ADC 16bits/105MSPS (LTC2217)
- Bus Driver - 16bits
- DAC 14bits - 275MSPS (DAC5672)
- Reconstraction RF LPF
- RF Power Amplifier
- Low Jitter VCXO 100MHz
- Low Noise Voltage regulators
------------------------------------------
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#spelex #electronicsprojects #hardware
#circuitboard #pcb #pcbdesign #altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #sdr #highspeedcircuit
#hamradio #radioamateur #3d

The tuned value of this variable capacitor, has to

The tuned value of this variable capacitor, has to be measured and replaced with a constant value capacitor.
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#spelex #electronicsengineering #electronicsprojects #hardware
#electronicengineer #electronicdesign
#radioelectronics
#rfdesign #rf
#electronicmeasurements
#lcr #rodeandschwarz #lcrmeter

This is a dual transistor with extended temperatur

This is a dual transistor with extended temperature range.

You can ask, why do we need to use so old transistors. For some type of electronics are very important such parameters as temperature, cosmic radiation effects etc. And long term changing of these parameters.
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#spelex #electroniccomponents
#transistor

Side view on the PCB without shielding cans. ----

Side view on the PCB without shielding cans.

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #sdr
#würthelektronik #rf #harwin
#shielding #analogfrontend
#analogdevices #texasinstruments
#harwin

Repaired, the RF baluns were re-soldered. The PCB

Repaired, the RF baluns were re-soldered.
The PCB is located on the electric pre-heater to avoid stressing the PCB.
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#spelex #pcb #printedcircuitboard #pcbassembly
#tools #baluns #preheater
#repairing

Side view on the PCB without shielding cans. ----

Side view on the PCB without shielding cans.

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #sdr
#würthelektronik #rf #harwin
#shielding #analogfrontend
#analogdevices #texasinstruments
#harwin

The linear Power Supply has not much High-frequenc

The linear Power Supply has not much High-frequency noise, but it has a 50Hz/100 Hz ripples, which can be easily filtered.
On the video are the 100Hz/150mV ripples at the output of the power supply with a resistive load 1 Amper.

DC - 7.4v/1A from Aiwa.
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#spelex #electronicstudent #electronicsengineering #electronicsprojects #hardware
#electronicengineer #electronicdesign
#circuitdesign
#electronicprojects
#electronicslovers #electronicsolution
#analogelectronics
#digitalelectronics
#diy #diyelectronics #powersupply #aiwa
#linearpowersupply #ripples #transformator

As I mentioned before, this plastic and transparen

As I mentioned before, this plastic and transparent stencil could be difficult to use few times.

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The project is an RF Analog Front End. (See my previous posts)
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#spelex #electronicsprojects #electronicdesign
#circuitboard #pcb #pcbdesign
#analogelectronics #digitalelectronics #rf
#soldering #stencil #transparentstencil #plasticstencil

This is an evaluation board of RF switch HMC DC -

This is an evaluation board of RF switch HMC DC - 3GHz.
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#spelex #electronicstudent #electronicmeasurement #electronicsengineering #electronicsprojects #hardware
#electronicengineer #electronicdesign
#circuitboard #pcb #pcbdesign
#circuitdesign
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #analogdevices #hittite

The PCB is soldered. I conduct a visual inspection

The PCB is soldered. I conduct a visual inspection.

On this photo is a clock module 100MHz for high-speed ADC and DAC.

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#circuitdesign #altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #rf
#rfdesign #sdr #balun
#würthelektronik
#microstrip #differentialsignal
#clock #vcxo

Assembling any PCB begins by checking the ESD conn

Assembling any PCB begins by checking the ESD connections.
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#spelex #esd #pcb #printedcircuitboard #pcbassembly #esdprotection
#tools #esdtools

Top view on the PCB without shielding cans. -----

Top view on the PCB without shielding cans.

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The project is an RF Analog Front End, which will be connected to an #FPGA board
(See my previous posts)
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#spelex #electronicsprojects #hardware #electronicdesign
#circuitboard #pcb #pcbdesign
#altium
#altiumdesigner
#radioelectronics
#analogelectronics #digitalelectronics #sdr
#würthelektronik #rf #harwin
#shielding #analogfrontend
#analogdevices #texasinstruments