Siglent SSA 3021X Spectrum Analyser
For now just some brief notes regarding the setup and configuration: - With the default settings, the noise floor shown on screen is around 60 dBm (38-40 dbuV). This is much worse than what is claimed in the specs, but works fine for the near-field probes, and relative basic measurements.
Notes on feasibility of "far-field" absolute measurements:
- In the instructions for TEM cells, the noise level for EMI compliance “fail” is 40dbuV… - To get the lowest noise floor, apply the following settings:
- Amplitude: Pre-amp on. Once the pre-amp is on, the Attenuator setting jumps from 20dB to 40dB (this probably means that the pre-amp adds 20dB amplification).
- Now it is possible to turn the attenuator down to zero. With nothing plugged in, the noise floor should now be around -100dBm (or around 7-10 dBuV). The near-field probe amplifier has a noise floor of -70dBm (or 37dBuV)
- bandwidth settings (BW): reducing the RBW from default (1MHz) to lower values (e.g. 100kHz) further reduces noise, but also affects the measured amplitude of peaks. Need to understand this better to work out the best settings for comparable absolute measurements.