Dsa815 spectrum analyzer yelloisw colors mean

Dsa815 spectrum analyzer yelloisw colors mean portable#

Check no chargers, soldering stations, lamps, etc. Check your tools during your troubleshooting process. These experiences prove that you must be careful when troubleshooting radiated or conducted emissions in your lab. The emissions disappeared from the instrument screen ( Figure 7 ).ДЇigure 7 Unplugging the spectrum analyzer's charge reduced background emissions.

Dsa815 spectrum analyzer yelloisw colors mean portable#

ДЇigure 6 My portable spectrum analyzer was connected to AC mains through its charger. That's when I found that my portable spectrum analyzer, used with a set of near field probes, was using the charger as shown in Figure 6.

What was wrong?ДЄrmed with the experience of the soldering station, I began looking around the room. It looked like the noise was not from the background (yellow color STOPPED in screen). With a near-field probe, we found that signals weren't radiating from the EUT. ДЇigure 5 These plots show background noise (yellow) and emissions from DUT (purple). While measuring radiated emissions at 3 m, we noticed a considerable level of emissions in the low frequency area as shown in Figure 5. We were testing a system with a power electronics converter at a company close to my lab. The second example is similar to the first. So, we found that a вЂњharmlessвЂќ soldering station was confusing us and hindering our ability to debug the problem for some time.

You can see the difference.ДЇigure 4 Background noise with and without soldering stations (EUT off). I then noticed that my soldering stations ( Figure 3 ) were sometimes on and sometimes off, as needed.ДЇigure 3 The instrumentation in my lab includes the soldering stations, as many do.ДЇigure 4 shows the background noise as measured in both situations. We tried to find the вЂњintermittentвЂќ emissions around the PCB of the EUT without success. To further complicate the problem, we found the emissions were not there all the time ( Figure 2 ).ДЇigure 2 The higher background noise masked some emissions from the EUT. Note the higher background noise was not present in the original (left) plot's blue trace. We tried to find those emissions in our DUT for some time without success. Emissions from a digital clock were found, but note the additional broadband emissions in the range 135 MHz-235 MHz. Then, we measured the EUT's emissions, shown in the right plot in Figure 1. But, the background noise is higher in the 135 MHz-235 MHz range. That measure was saved in the screen as a reference.ДЇigure 1 The left plot shows background noise while the right plot shows emissions (red) and background noise (blue). Emissions from FM broadcast transmitters in 88-108MHz are clearly identified.

In this case, you can see in Figure 1 (left) how the background noise was before measuring the DUT. Then, I try to find the frequencies with problems in my lab, identifying the background noise and then debugging as the EUT goes through its operations. Usually, I have some kind of emissions results from a laboratory with a shielded chamber-my reference data-because I donвЂ™t have a chamber. While in my lab one day, I was trying to solve a radiated emissions problem from a device. One instance occurred in my lab and the other at a small company close to my University. Let me explain using two examples of unexpected вЂњproblemsвЂќ while troubleshooting radiated emissions that weren't caused by my EUT. Sometimes, you need a special вЂњsixth senseвЂќ that only comes from experience because in some cases, your problems aren't even related with the EUT (equipment under test). You need time, you need a strategy, and you need to remain calm. Successfully troubleshooting EMI/EMC problems isn't easy.