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Use new FIR decimation in FSK demodulator.

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Reduces FIR calculation effort when output samples are skipped at FIR filter, not after.
This commit is contained in:
Jared Boone 2015-11-04 09:49:14 -08:00
parent 86b068be62
commit 26c23dc8a0
2 changed files with 3 additions and 3 deletions
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4
firmware/baseband/proc_fsk.cpp
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@ -65,7 +65,7 @@ void FSKProcessor::execute(buffer_c8_t buffer) {
/* 153.6kHz complex<int16_t>[128]
* -> FIR filter, <?kHz (?fs) pass, gain 1.0
* -> 76.8kHz int16_t[64] */
* -> 19.2kHz int16_t[16] */
auto channel = channel_filter.execute(decimator_out, work_baseband_buffer);
/* 76.8kHz, 64 samples */
@ -79,7 +79,7 @@ void FSKProcessor::execute(buffer_c8_t buffer) {
// 76.8k
// TODO: Factor out this hidden decimation magic.
for(size_t i=0; i<channel.count; i+=4) {
for(size_t i=0; i<channel.count; i++) {
// TODO: No idea why implicit cast int16_t->float is not allowed.
const std::complex<float> sample {
static_cast<float>(channel.p[i].real()),

2
firmware/baseband/proc_fsk.hpp
View File

@ -55,7 +55,7 @@ private:
ChannelDecimator decimator { ChannelDecimator::DecimationFactor::By16 };
const fir_taps_real<64>& channel_filter_taps = taps_64_lp_031_070_tfilter;
dsp::decimate::FIRAndDecimateComplex channel_filter { channel_filter_taps.taps, 2 };
dsp::decimate::FIRAndDecimateComplex channel_filter { channel_filter_taps.taps, 8 };
dsp::matched_filter::MatchedFilter mf { baseband::ais::rrc_taps_128_decim_4_p, 1 };