[Discuss-gnuradio] Goertzel vs FIR bandpass

[Marcus D. Leech]

I tried an experiment this evening with my 6-channel VLF receiver, which 
uses a sound-card (sampled at 96KHz or 192KHz) to sample
  a VLF loop antenna and amplifier, and then do power detection (and 
other things) over six discrete channels, arbitrarily spaced.

The version that I've been using up until now uses a FIR bandpass filter 
for each channel, followed by an utterly-uninteresting
  power-detector chain.

I didn't know anything about the Goertzel transform until a couple of 
days ago, and decided to substitute an equivalent Goertzel
  transform for each channel, to see if I could save any CPU by doing 
so. The result was that I can save about 15% by going  to
  the Goertzel transform, instead of an FIR filter with 
roughly-equivalent bandwidth.

I'm going to let it run for a couple of days to compare sensitivity.

For equally-spaced channels (which isn't the case here), an FFT might 
also be useful and slightly cheaper than a discrete FIR filter
  for each channel.


--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org