Git-Mirrors/portapack-mayhem
1
0
Fork 0
mirror of https://github.com/eried/portapack-mayhem.git synced 2025-07-30 10:09:25 -04:00
Code Issues Projects Releases Packages Wiki Activity

Generalize fir_and_decimate_by_2_complex_fast.

Browse source 
Permit decimation_factors other than 2.
Permit tap counts != 64 (but still must be multiple of 8).
Half the amount of tap memory required.
Performance is significantly degraded due to greater flexibility -- most likely due to separate sample buffer shift phase, instead of performing shift during output sample calculation.
This commit is contained in:
Jared Boone 2015-11-03 16:17:59 -08:00
parent be78ed657f
commit cde15e4271
2 changed files with 41 additions and 20 deletions
Download patch file Download diff file Expand all files Collapse all files

8
firmware/baseband/dsp_decimate.hpp
View file

@ -84,7 +84,8 @@ size_t fir_and_decimate_by_2_complex_fast(
complex16_t* const dst_start,
complex16_t* const z,
const complex16_t* const taps,
const size_t taps_count
const size_t taps_count,
const size_t decimation_factor
);
class FIRAndDecimateBy2Complex {
@ -100,7 +101,7 @@ public:
FIRAndDecimateBy2Complex(
const size_t taps_count
) : samples_ { std::make_unique<samples_t>(taps_count) },
taps_reversed_ { std::make_unique<taps_t>(taps_count * 2) },
taps_reversed_ { std::make_unique<taps_t>(taps_count) },
taps_count_ { taps_count }
{
}
@ -111,14 +112,13 @@ public:
) : FIRAndDecimateBy2Complex(taps.size())
{
std::reverse_copy(taps.cbegin(), taps.cend(), &taps_reversed_[0]);
std::reverse_copy(taps.cbegin(), taps.cend(), &taps_reversed_[taps.size()]);
}
buffer_c16_t execute(
buffer_c16_t src,
buffer_c16_t dst
) {
const auto dst_count = fir_and_decimate_by_2_complex_fast(src.p, src.count, dst.p, &samples_[0], &taps_reversed_[0], taps_count_);
const auto dst_count = fir_and_decimate_by_2_complex_fast(src.p, src.count, dst.p, &samples_[0], &taps_reversed_[0], taps_count_, decimation_factor);
return { dst.p, dst_count, src.sampling_rate / decimation_factor };
}