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Refactor IIRBiquadFilter to separate configuration structure.

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This commit is contained in:
Jared Boone 2015-08-04 15:00:38 -07:00
parent 76df4f0369
commit caef87fe90
2 changed files with 24 additions and 24 deletions
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18
firmware/baseband/dsp_iir.hpp
View File

@ -26,16 +26,19 @@
#include "dsp_types.hpp"
struct iir_biquad_config_t {
const std::array<float, 3> b;
const std::array<float, 3> a;
};
class IIRBiquadFilter {
public:
// http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
// Assume all coefficients are normalized so that a0=1.0
constexpr IIRBiquadFilter(
std::array<float, 3> b,
std::array<float, 3> a
) : b(b),
a(a)
const iir_biquad_config_t& config
) : config(config)
{
}
@ -51,8 +54,7 @@ public:
}
private:
const std::array<float, 3> b;
const std::array<float, 3> a;
const iir_biquad_config_t config;
std::array<float, 3> x { { 0.0f, 0.0f, 0.0f } };
std::array<float, 3> y { { 0.0f, 0.0f, 0.0f } };
@ -63,8 +65,8 @@ private:
y[0] = y[1];
y[1] = y[2];
y[2] = b[0] * x[2] + b[1] * x[1] + b[2] * x[0]
- a[1] * y[1] - a[2] * y[0];
y[2] = config.b[0] * x[2] + config.b[1] * x[1] + config.b[2] * x[0]
- config.a[1] * y[1] - config.a[2] * y[0];
return y[2];
}

30
firmware/baseband/main.cpp
View File

@ -175,6 +175,16 @@ private:
}
};
static constexpr iir_biquad_config_t audio_hpf_config {
{ 0.93346032f, -1.86687724f, 0.93346032f },
{ 1.0f , -1.97730264f, 0.97773668f }
};
static constexpr iir_biquad_config_t non_audio_hpf_config {
{ 0.51891061f, -0.95714180f, 0.51891061f },
{ 1.0f , -0.79878302f, 0.43960231f }
};
class FMSquelch {
public:
bool execute(buffer_s16_t audio) {
@ -203,10 +213,7 @@ private:
// nyquist = 48000 / 2.0
// scipy.signal.iirdesign(wp=8000 / nyquist, ws= 4000 / nyquist, gpass=1, gstop=18, ftype='ellip')
IIRBiquadFilter non_audio_hpf {
{ 0.51891061f, -0.95714180f, 0.51891061f },
{ 1.0f , -0.79878302f, 0.43960231f }
};
IIRBiquadFilter non_audio_hpf { non_audio_hpf_config };
};
static volatile bool channel_spectrum_request_update { false };
@ -332,10 +339,7 @@ private:
const fir_taps_real<64>& channel_filter_taps = taps_64_lp_031_070_tfilter;
dsp::decimate::FIRAndDecimateBy2Complex<64> channel_filter { channel_filter_taps.taps };
dsp::demodulate::AM demod;
IIRBiquadFilter audio_hpf {
{ 0.93346032f, -1.86687724f, 0.93346032f },
{ 1.0f , -1.97730264f, 0.97773668f }
};
IIRBiquadFilter audio_hpf { audio_hpf_config };
};
class NarrowbandFMAudio : public BasebandProcessor {
@ -393,10 +397,7 @@ private:
dsp::decimate::FIRAndDecimateBy2Complex<64> channel_filter { channel_filter_taps.taps };
dsp::demodulate::FM demod { 48000, 7500 };
IIRBiquadFilter audio_hpf {
{ 0.93346032f, -1.86687724f, 0.93346032f },
{ 1.0f , -1.97730264f, 0.97773668f }
};
IIRBiquadFilter audio_hpf { audio_hpf_config };
FMSquelch squelch;
};
@ -461,10 +462,7 @@ private:
const fir_taps_real<64>& audio_filter_taps = taps_64_lp_156_198;
dsp::decimate::FIR64AndDecimateBy2Real audio_filter { audio_filter_taps.taps };
IIRBiquadFilter audio_hpf {
{ 0.93346032f, -1.86687724f, 0.93346032f },
{ 1.0f , -1.97730264f, 0.97773668f }
};
IIRBiquadFilter audio_hpf { audio_hpf_config };
};
class FSKProcessor : public BasebandProcessor {