Hi,
I’ve seen a number of audio spectrum analyser designs that use FFT or similar to get the spectrum. This usually means a higher end micro and a bit of memory.
For some applications like a guitar tuner or whatever, the higher resolution and phase information from the FFT isn’t needed.
Has anyone seen designs where digital potentiometers are used to sweep a narrow band filter across the desired range, then measured using a A/D pin on a low end micro?
I suppose the limitation would be the response time of the filter circuit, but don’t know enough about them to gauge whether this is a real limitation in practice.
Also does anyone know how to convert the oscillating signal from the filter to an measure of the amplitude. My guess would be to rectify and low pass filter the AC signal…but maybe there are other ideas.
Phil