Spectrum averaging
Implementation of averaging on the spectrum displays. This concerns the main window spectrum display and also the spectrum display on the following plugins: Broadcast FM demodulator, Channel analyzer, SSB demodulator, UDP source and UDP sink.
There are two modes for averaging N samples:
- moving average: there is one FFT sample out for every FFT sample in and the average is made on the N last samples
- fixed average: there is one FFT sample out for every Nth FFT sample the average is also made on the N last samples but averaging is done one after the other and not by sliding the average window. The effect is to slow down the waterfall by the averaging value.
There are two new controls on the spectrum GUI for the averaging mode and value and other controls have been shuffled around a little bit. The details of the GUI can be found here: https://github.com/f4exb/sdrangel/tree/master/sdrgui#4-spectrum-display-control