I have used Analog Discovery 1 extensively for various audio measurements (Bode plots, photonic measurements, scope noise measurements etc.) and have just started to use the Waveforms Spectrum Analyzer. I have made quite a few real-time noise measurements using a very low noise well calibrated 24 bit/96kHz sound card down to the uVrms level using a steep 46kHz low pass filter and also a similar 20kHz 5th order LPF. So these are time-domain analog measurements within a well defined "noise bandwidth". With sufficiently high noise levels (say +20mVrms well above the ~ 0.5mV noise floor of the Discovery scope inputs) my independent total noise measurements agree closely with the Discovery scope RMS noise readings. I generally calculate a SNR by dividing a signal level (typically 1-2 dBV) by this total RMS noise value (20kHz filtered and sometimes adding an A-Weight Filter to check product specs).
So my question is about the noise-floor value displayed in the Waveforms Spectrum Analyzer for the FFT option and dBV vertical scaling. I realize that the noise floor values are values related to the bin frequency size and the filtering related to the type of sample. I'd like to:
(1) numerically reconcile my total noise measurements within a specified noise BW (above) with noise floor display provided by Spectrum Analyzer.
(2)numerically reconcile my SNR (relative to the peak signal level) with the SNR result calculated by Spectrum Analyzer (my simple comparison of SNR is off by at least 3dB. What is the effective "noise bandwidth" range used by Spectrum Analyzer?
This provides a bit of background including a link to other articles I've written about my usage of Analog Discovery 1
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MitchG
I have used Analog Discovery 1 extensively for various audio measurements (Bode plots, photonic measurements, scope noise measurements etc.) and have just started to use the Waveforms Spectrum Analyzer. I have made quite a few real-time noise measurements using a very low noise well calibrated 24 bit/96kHz sound card down to the uVrms level using a steep 46kHz low pass filter and also a similar 20kHz 5th order LPF. So these are time-domain analog measurements within a well defined "noise bandwidth". With sufficiently high noise levels (say +20mVrms well above the ~ 0.5mV noise floor of the Discovery scope inputs) my independent total noise measurements agree closely with the Discovery scope RMS noise readings. I generally calculate a SNR by dividing a signal level (typically 1-2 dBV) by this total RMS noise value (20kHz filtered and sometimes adding an A-Weight Filter to check product specs).
So my question is about the noise-floor value displayed in the Waveforms Spectrum Analyzer for the FFT option and dBV vertical scaling. I realize that the noise floor values are values related to the bin frequency size and the filtering related to the type of sample. I'd like to:
(1) numerically reconcile my total noise measurements within a specified noise BW (above) with noise floor display provided by Spectrum Analyzer.
(2)numerically reconcile my SNR (relative to the peak signal level) with the SNR result calculated by Spectrum Analyzer (my simple comparison of SNR is off by at least 3dB. What is the effective "noise bandwidth" range used by Spectrum Analyzer?
This provides a bit of background including a link to other articles I've written about my usage of Analog Discovery 1
60dBLowNoiseAudioAmplifier
Thanks.
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