How do you handle interference in electronic testing?

1 Identify the source

Identifying the source and type of interference is the first step. To observe the frequency, amplitude, and waveform of the noise, you can use a spectrum analyzer, an oscilloscope, or a logic analyzer. Near-field probes and loop antennas can be used to locate the direction and distance of the source. Common sources of interference include conducted noise, which travels through wires, cables, or connectors and is caused by power supply fluctuations, ground loops, or switching devices; radiated noise, which travels through the air or space and is caused by electromagnetic fields, radio frequency signals, or electrostatic discharge; and crosstalk, which occurs when signals from one circuit or channel interfere with another due to capacitive or inductive coupling or poor shielding or isolation.

2 Choose the right equipment

When choosing the right equipment for your testing and measurement, you should take into account several factors such as bandwidth, sensitivity, and resolution. The bandwidth should be higher than the highest frequency of your signal of interest and lower than the lowest frequency of the interference. The sensitivity should be lower than the lowest amplitude of your signal of interest and higher than the highest amplitude of the interference. The resolution should be higher than the smallest change in your signal of interest and lower than the smallest change in the interference. All of these factors are important to consider when selecting the right equipment for your testing and measurement needs.

3 Apply the best practices

The third step is to apply the best practices for your testing and measurement. You should use shielded cables and connectors and twisted pairs or differential signals for both input and output signals, connecting the shields to a common ground point. Filters or attenuators can be used to remove or weaken the noise outside or inside your bandwidth of interest, respectively. Additionally, proper grounding and layout should be implemented to avoid ground loops, crosstalk, or other sources of noise. Following these guidelines will help to reduce the noise and ensure accurate testing and measurement.

4 Test and verify

The final step in testing and measurement is to test and verify. To do this, you should compare your results with a known standard or reference, such as a calibrated signal generator, a reference resistor, or a certified meter. Additionally, it's important to repeat your testing and measurement under different conditions, such as different temperatures, voltages, or distances. This will help you check the stability and repeatability of your results. Lastly, you should document your testing and measurement, including the equipment, settings, procedures, and results. This will help you analyze your results and communicate your findings. Interference is inevitable in electronic testing and measurement but can be handled with proper techniques and practices. With these steps, you can minimize the impact of interference and improve the quality and reliability of your testing and measurement.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?