On 20/07/15 17:32, Mark Morgan Lloyd wrote: > Lukasz Sokol wrote: >> >> It's been years since I had anything to do with DSP, unfortunately, >> but with the FFT running on the sliding 26-sample-long window, and >> a /reverse/ FFT to produce the 26-long sample from just having a >> byte or 2 written to an array, the kind of SIMD processing probably >> won't be very time consuming... and, operating on a fixed size >> array, would be of fixed-processing-time, which is usually handy. > > Thanks, noted. I must admit that I've never dabbled directly with > FFT, but perhaps now is the time to start. I need to do a couple of > test simulations first to demonstrate that working in the frequency > domain is more promising than the time domain (I'm having to fight > off the boss's suggestion that I simply time zero crossings). > >> Just my £0.02p :) el es > > Worth more than you think > http://www.bbc.co.uk/news/uk-england-berkshire-33586245 :-) > :) Thinking about it some more, it could actually be true that FFT/DFT is overkill.
For detection you need 4 specialized discrete band-pass (1 freq pass) filters, checking their output 'power' (side note : moving average can be used as detector on their outputs) and you can use them for sending too - just feed them white noise to the input :) there are some advantages to that which this email is too short to contain ;) el es _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal