I have some iq data recordings of a 2-FSK waveform that I've created periodograms from. How do you estimate the SNR of this waveform in the frequency domain? I've heard two opinions:
- Integrate the signal band power over the excursion
- Find a clear area of the spectrum and integrate the noise power over the same bandwidth
- Divide the two quantities: SNR = signal power/noise power
- This seems weird because FSK is just two tones and integrating the signal over the excursion is just integrating a lot of noise and very little signal
- Find the peak signal power of one of the tones
- Estimate the median of the noise floor power
- Divide peak signal by median of noise floor: SNR = peak / median
- This also seems weird because depending on the snapshot of data, the amplitude of the tones is different. SNR isn't changing but this method doesn't give a constant SNR.
If I could collect the same iq data with the waveform turned off (just receiver noise), would it make the calculation any simpler?