List of solved problems
Below is a list of common EMI/EMC problems that were solved. It does not cover all cases and shows a variety of problems.
| Project | Description of the problem | Source of the problem |
|---|---|---|
| Wireless IoT sensor (2.4 GHz) | Wireless IoT sensor with Time Division Multiple Access (TDMA) began to malfunction (in a time-domain window) at edge temperatures. | The level of an internally radiated electromagnetic interference (EMI) from a DC/DC converter raised with temperature changes and influenced the very sensitive (low power) internal RTC oscillator of the MCU. |
| Automated Test Equipment (Automation) | During installation, the automated control system showed the impossibility of measuring analog signals with the required accuracy. The analog module manufacturer guarantees the required performance. | External noise (EMI) interferred with the analog measurement module. The robotic equipment generated noise that entered the analog module inputs. Cables and grounding required reconnection. |
| Infrared Spectrometer (Food Analysis) | The EMI Radiated Emission (RE) test failed. | The device emits RF signals at the junction of the case and cover. The measurements without the metal cover show strong EMI levels. A signal integrity issue was detected on the board between the FPGA and the Clock distribution chip. In addition, an optimization of the mechanical design was proposed to reduce the EMI level and pass the EMC test. |
| Industrial PID Controller | Problem measuring the accuracy of analogue signals in harsh industrial conditions. (PT100, PT1000, NTC, Thermocouple). | EMC Radiated Susceptibility issue of analogue inputs. Strong RF interference is rectified by the internal elements of the amplifier chip and appear as a DC output error in the form of an offset. |
| Instrumental Electronics of a Satellite Navigation System (Spacecraft) | Support in performing a set of conducted EMC analyses and measurements according to the standards ECSS / MIL-STD-461. | Simulation model extraction of a DC/DC converter (Common and Differential Mode), Input Filter design. Analysis/Simulation/Measurement of levels of Conducted Emissions, Conducted Susceptibility, Fast and Slow transient spikes. |
| Advanced Driver Assistance Systems (ADAS) / Time of Flight (ToF) LIDAR System (Automotive) | ADC – Based Optical ToF System had a lower resolution than expected. The evaluation board worked well. There was a lot of noise in the converted ADC values. The form of digital signals at the ADC output was normal. | There were no signal integrity issues between ADC and FPGA. Ripples from a switching power supply (SMPS) modulated the clock signal source, which created additional jitter and reduced the signal-to-noise ratio (SNR) of the ADC. The SMPS ripples reached the clock source through a non-optimal PCB grounding concept. |
| Instrumental Electronic Device of a Space System (Spacecraft) | Unable to perform high accuracy measurements in the gas – optical system. A linewidth of the laser measurement system was wider than required and had unwanted spectrum spurs. | The performance of a low noise module was affected by the Signal Integrity (SI) on the PCB. High-speed digital signals between an FPGA and components on the board created electromagnetic interference (EMI) that interfered with low-noise analogue circuits and destroyed EMC harmony in the system. The PCB layout and grounding concept required optimization. |
| Processor Module of a Medical Device (ECG Machine) | A Radiated Emission (RE) test failed by around 4-7 dB in the 100 MHz range. | Signal layout and ground routing around the Ethernet connector needed optimization. The Ethernet PHY must be isolated according to the standard and any noise picked up on the cable should not be coupled back into the rest of the board. |
| Wireless IoT sensor (868 MHz) | The useful radio communication range between sensors and the central module was inadequate. An evaluation board with this type of RF chip works as expected. The chip connection and antenna are from a reference design. | Internal electromagnetic interference (EMI) between the MCU, the DC/DC converter, the MEMS sensor and the RF transceiver. The power distribution network of the board needed optimization and filtering. And the RF chip must be isolated from the rest of the circuit. |
| Blood Sugar Measurement Device (Medical) | The measurement accuracy was reduced depending on some temperatures. The device worked well from +5° to +10° and from +28° to +40°. In the range from +10° to +28° the device showed inaccurate values. Evaluation boards worked well. | Because of slight variations or mismatches in unsynchronized DC/DC converters, the clock frequency of the converters, due to temperature, became almost the same. They generated additional EMI (beat frequencies), which affected the sensitive analogue circuits and ADC – 24bits. |
| High-Frequency Digital Communication System (RF – QAM64) | 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. | 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. |
| Powerful TEC Driver (200W) for Laser Measuring System (Spacecraft) | The driver generated strong electromagnetic interference (EMI) that interfered with low noise electronics. | Parasitic elements of Power MOSFETS on the PCB created an antenna that emits ringing. Optimization of grounding and damping were required. |
| Optical Communication System | The Eye Diagram of the demodulated signal showed a reduction in the size of the eye opening, which increased the potential for data errors. | The Laser Driver generated too much noise that increased Bit Error Rate (BER). |
| Embedded Single Board Computer Module CPU/FPGA (Automotive) | A high speed digital interface on the board had an increased bit error rate (BER). There was likely a signal integrity issue on the PCB, but the PCB had been carefully designed with signal integrity in mind. The layout of the high speed signals on the PCB was developed using a simulation tool. | Power Integrity Issue on the board. The Power Distribution Network (PDN) had a latent resonance peak that causes jitted in the power rails. This jitter impacted the threshold level of the MCU and FPGA, thereby compromising the integrity of the High-Speed Signal (SI) on the PCB. |
| Instrumental Electronic Device of a Space System (Spacecraft) | Development of a grounding concept diagram that describes deliberate grounding separation, minimization of ground loops and reduction of the generation of EMI between moduless. This diagram also includes analogue and digital signal groups, shows potential collisions and suggests ways to mitigate potential interference. | 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. |
| Vibration Analysis and Multi-Channel Data Acquisition Systems (Measurement of Turbines, Motors, Gearboxes) | 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. | 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. |
| Entertainment System (Automotive) | 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. | 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. |
| Home Automation Controller (Smart House) | The pre-compliance test for EMI Radiated Emission failed. | Signal Integrity problem on the PCB. Incorrect routing of digital signals when traversing PCB layers. |
| Smart House System | Poor voice quality when making a phone call or a voice command. | An internal EMC problem due to the emission of digital signals causing interference to on the audio intercom system. |
| Security System | 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. | Incorrect system behaviour due to problems with ESD Immunity at input/output signals. |
| Industrial Controller | The pre-compliance test for EMI Radiated Emission failed. | Signal Integrity problem, which caused the EMI problem. Insufficiently thought out the PCB design of the High-Speed Ethernet controller and ground. |
| Computer Module of a Vending Machine | The pre-compliance test for EMI Radiated Emission failed by around 6-8 dB in the 120 MHz range. | There was a signal integrity problem of the high speed interfaces which caused the EMI problem. |
| NFC-A (RFID) Communication | The pre-compliance EMV test failed. The transmitted NFC waveform had overshoots and is not following the standard. | Impedance matching problem between the antenna and the RF amplifier. |
| High Precision Industrial PID Controller | Problem measuring the accuracy of analogue signals (PT100, PT1000). | 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. |
| NFC-B (RFID) Communication | The pre-compliance EMV test failed. The device did not receive the NFC test signal from the distance specified in the standard. The TX channel worked fine. | The RX channel was not sensitive enough due to non-optimized connections (Antenna-RX-TX). |
| Tiny Tracker System (IoT) | The device did not receive a stable GNSS signal. An evaluation board with such a chip and antenna works quite well. | 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. |
| Smart Metering with Sigfox (IoT) | 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. | 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. |
| Wireless IoT Device for Sports | The battery life of the prototype is too short. The breadboard showed good results. | The very low power system with a high impedance circuit has a susceptibility issue. The switches (MOSFETs) were supposed to disconnect circuits with very low leakage currents, but due to this problem they did not disconnect the load completely. Hardware and software optimization was required. |
| Tiny IoT Device | The device was intermittent and did not consistently work as expected. This was visible when people moved near the device. | ESD Immunity was poor. Moving people generate electrostatic discharge that causes unwanted disturbances (level upset) in the unprotected circuit. |
| Wearable IoT device | An EMC/EMI issue that affected normal system operation. | Fast switching of MOSFETs caused high-frequency switching ringingon the PCB (ground bouncing). Generated EMI influenced sensitive circuits. Power Integrity and control circuit optimization are required. |
| Instrument Electronics of a Space System (Spacecraft) | The electronic module generated a high level of Common-Mode (CM) Conducted Emissions (CE) at the primary power side of the DC/DC converter. | 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). |
| Instrumental Electronic Device of a Space System (Spacecraft) | 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. | 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. |
| Instrumental Electronic Device of a Space System (Spacecraft) | The analogue module was heavily influenced by the rest of the system. It was unstable with a variable measurement error. | The analogue module was affected by the Signal (SI) and Power Integrity (PI) of the PCB. High-speed digital signals on the board and improper decoupling created electromagnetic interference (EMI) that interfered with low-noise analogue circuits and destroyed EMC harmony in the system. |
| Instrumental Electronic Device of a Space System (Spacecraft) | The Laser Diode Driver/Modulator had undesirable oscillations / instability under certain conditions. | Conductive Electromagnetic Interference (EMI) such as current surges from adjacent circuits and PCB layout affected the target circuit and caused instability. The stability factor of the circuit and PCB layout needed optimization. |
| Power Module for Spacecraft Electronics | The pre-compliance test for EMC emissions failed. | Current loops on the PCB, non-optimized placement and routing of decoupling capacitors. Common and differential mode filters needed optimization. |
| Processor Module of a Medical Device (ECG Machine) | The system didn’t work consistently. The analogue Front-End did not communicate properly with the FPGA at limit temperatures. Evaluation boards worked well. | The interconnected components were affected by a Simultaneous Switching Noise (SSN) problem on the PCB. In turn, the FPGA was not properly decoupled (Power Integrity problem). Such noise on the board creates electromagnetic interference (EMI) that interferes with digital signals and alters their shape and timing. |
| Instrumental Electronic Device of a Space System (Spacecraft) | EMC/EMI problems in the system that degraded measurement performance. | The root cause of the problem was integrated noise that appears and travels in a chain (Power Supply – Filters – Voltage Regulators – Filters – Low Noise Analog Electronics). The total noise (leakage) in the system was not just distributed, but also amplified and degraded the performance of the low noise analogue electronics. |
| Instrumental Electronic Device of a Space System (Spacecraft) | Unknown disturbances on the board that didn’t allow retrieval of the desired resolution of the ADC. The instrument measures DC voltage and very low frequency signals with insufficient accuracy. At some frequencies, the signal could not be measured accurately enough. | Found a bottle neck in the analogue input chain: LPF – Amplifier - Anti-Aliasing Filter – ADC. The cause of the problem was a discrepancy between the ADC settings and the circuit parameters at high frequencies. |
| Optical(Laser) High Speed Communication Module | The Linewidth (PhaseNoise) at the output of the Laser Driver had unwanted spurs that compromised accuracy. | The internal linear power supply and filter had noise peaks that modulated the laser signal. |
| Optical(Laser) High-Speed Communication Module (Spacecraft) | The synchronous H-bridge TEC driver generated a substantial amount of noise (EMI) that affected the low noise analogue electronics. | The root causes of the problem were the high switching ringing amplitude at the output of the switching MOSFETs and non-optimized placement and routing of the decoupling capacitors. |
| Power Module of Spacecraft Electronics. | The analogue temperature controller had a variable error when testing the TEC synchronous H-bridge driver in a temperature chamber. | The electromagnetic interference (EMI) level of the switched TEC driver changed with temperature and disturbed the stability of the analogue temperature controller. |
| Instrumental Electronics Device (Spacecraft) | Support to design/optimize the architecture of instrumental electronics that perform low noise measurements. | There was a potential risk of electromagnetic interference from digital signals (Signal Integrity) that can disrupt low noise signals. |
| Ultrasound Imaging Systems (Medical) | The system had a intermittent error during measurements. Low noise analogue signals from ultrasound transducers were disturbed by the rest of the electronics. | The system grounding concept needed to be optimized to reduce internal EMI (Signal Integrity) and improve EMC in the module. |
| Instrumental Electronic Device of a Space System (Spacecraft) | Sensitive signals from a precise acquisition system suffered from disturbances. | The noise emitted by the power supply entered the amplifier and mixed with the input signal. Sensitive circuits needed protection and filtration. |
| High-Frequency Precision Time System | There were unwanted spurs in an RF signal (~4GHz) on a low noise analogue board. | The source of the unwanted spurs was traced on the PCB. The digital circuit of telemetry generated distortions that were coupled with the PLL Synthesiser. The unwanted EMI modulated the power lines of the PLL reference clock, which in turn caused spurs in the PLL bandwidth range. |
| Tiny IoT Device | The microcontroller (MCU) intermittently stopped saving the information to external memory. The evaluation boards worked well. | A signal integrity issue was identified. The trace capacitance of the 8-layer PCB was too large compared with the weak drive capability of the MCU. |
| Wearable GNSS Tracker | Schematic/PCB Review | Optimized the schematic and grounding of the PCB to reduce potential EMC/EMI problems. |
| Instrumental Electronic Device of a Space System (Spacecraft) | The Laser Driver Electronics were sensitive to cosmic radiation - Single Event Transient (SET). Cosmic rays can сause a strong increase in current through the laser diode and damage it. The laser must be protected against fast transients and current spikes. | Fast control signals affect the Laser Driver. It was necessary to implement a filter to mitigate the effects of SET. |
| Wearable Authorization terminal | Support of the pre-compliance test at the EMC Laboratory. The Radiation Emission (RE) results showed a few spurs above the limit at 300 MHz. | The EMI problem was caused by incorrect clock routing on the PCB. |
| Instrumental Electronic Device of a Space System (Spacecraft) | The performance of sensitive analogue electronics was disturbed by other modules via the backplane board. | Cross coupling between the signals on the Power and the Backplane PCB destroyed EMC harmony in the system. |
| Laser Communication System | The transmitted laser signal has unacceptable jitter, which reduces the signal's eye diagram and increases the bit error rate (BER) of the system. | Insufficiently suppressed switching ringing in an SMPS TEC driver generated unwanted spurs, that affected the low noise laser driver. The sensitive driver modulates the transmitted signal with additional interference that results in increased jitter and a closing of the eye diagram. |
| Three - Phase Frequency Converter for a 10 kW Motor (Automation) | The device was successfully pre-tested for radiated and conducted emissions. But the control electronics were unstable and the problem arises at maximum load. | The return currents of the fast switching elements wandered around sensitive analogue electronics trying to find its way back creating noisy interference as it goes. |
| Artificial Respiration Apparatus (Medical) | Design support (schematic, PCB, case and cabling) to minimize electromagnetic interference (EMI) and ESD. | - |
| Ultrasonic Diagnostic Device (Medical) | The entire system structure did not pass the pre-compliance EMC test due to Radiated Susceptibility. | The entire system structure did not pass the pre-compliance EMC test due to Radiated Susceptibility. |
| High-end Ultrasonic Meter for Heating and Cooling Consumption (HVAC) | Intermittently after a short power restart, the device records incorrect measurements. | A power sequence problem that caused a "Latch-Up" of an operational amplifier. |
| Electrocardiogram Equipment (ECG Medical) | A medical device that monitors the R-Wave in a QRS complex performed lower than expected. Something was interfering with the sensitive sensors and disturbing measurements. | A low-level signal (in the band from 10Hz to 40Hz) is being sensed by sensitive amplifiers and digitized with a help of the A/D converter. The Power Supply of the ADC and Clock was a source of pollution (EMI) and needed optimization. One of the proposed solutions was implemented in firmware and showed good performance. Serial production can be continued without changing the printed circuit boards. The hardware changes can be done in the next version of the device. By making changes to the hardware, performance will be increased and current consumption will be reduced. |
| Point of Sale using LoRaWAN (IoT, Retail) | The communication range of the wireless devices was too short. The evaluation board works well. The antenna was designed with the help of a simulation program. | Internal electromagnetic interference (EMI) between the DC/DC converter, the MCU and the RF transceiver. The power distriburion network of the board needed optimization, especially grounding. The return currents of the fast switching elements wandered around the RF transceiver trying to find its way back creating noisy interference as it goes., which must be isolated from the rest of the circuit noise. |
| Entertainment Media System | The sound quality was poor, especially in the pauses between music. The system consists of a switching power supply, Raspberry PI, stereo audio amplifier and control electronics for the actuators. | A ground loop was identified that directed the digital signal noise to the audio amplifier in the system and created EMC disharmony in the system. |
| Project | Description of the problem | Source of the problem |
