Are you measuring the right noise?

Video Description

Free mini-course: https://www.hans-rosenberg.com/minicourse_account_youtube?utm_source=yt-d-v16 Full course info: https://www.hans-rosenberg.com/epdc_information_yt?utm_source=yt-d-v16 Why your SNR reading might be wrong and how to verify it using a normal PC. I once bought a 60.000 euro phase-noise analyzer and I discovered the phase noise software on the instrument gave me false readings. So I never trust any piece of equipment without verifying it myself! I recently bought a QA403 high performance USB audio-analyzer that I intend to use for precision noise-floor measurements on some LNAs I’ll be using on future videos. However… Is it accurate? Turns out there are a few small errors in the software and the QA403 hardware is absolutely fantastic. In this video, I show you how you can create very accurate calibration signals using Python and a normal PC and verify the noise-floor and snr measurements of the QA403 software. The key to success here is linking the voltage of the noise-floor (which is hard to measure) solidly to RMS voltage of a sine-wave (which is very easy to measure) so that a simple multimeter can be used to know exactly what the noise-voltage of the noise-floor is. An SNR or Signal to Noise Ratio measurement is the key to linking these together in the QA403. During the process, you’ll learn how to add noise sources correctly, how to convert noise-floors into RMS noise-voltages, how SNR is calculated, what the absolute level of the noise-floor is in sampled signals and more.