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Add IIR configs for lower audio sampling rates.

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This commit is contained in:
Jared Boone 2016-01-29 15:32:32 -08:00
parent a2a169352c
commit 0e436ded14
1 changed files with 26 additions and 0 deletions
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26
firmware/baseband/dsp_iir_config.hpp
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@ -36,6 +36,18 @@ constexpr iir_biquad_config_t audio_48k_hpf_300hz_config {
{ 1.00000000f, -1.94447766f, 0.94597794f }
};
// scipy.signal.butter(2, 300 / 8000.0, 'highpass', analog=False)
constexpr iir_biquad_config_t audio_16k_hpf_300hz_config {
{ 0.92006616f, -1.84013232f, 0.92006616f },
{ 1.00000000f, -1.83373266f, 0.84653197f }
};
// scipy.signal.butter(2, 300 / 4000.0, 'highpass', analog=False)
constexpr iir_biquad_config_t audio_8k_hpf_300hz_config {
{ 0.84645925f, -1.69291851f, 0.84645925f },
{ 1.00000000f, -1.66920314f, 0.71663387f }
};
// scipy.signal.iirdesign(wp=8000 / 24000.0, ws= 4000 / 24000.0, gpass=1, gstop=18, ftype='ellip')
constexpr iir_biquad_config_t non_audio_hpf_config {
{ 0.51891061f, -0.95714180f, 0.51891061f },
@ -49,6 +61,20 @@ constexpr iir_biquad_config_t audio_48k_deemph_300_6_config {
{ 1.00000000f, -0.96148145f, 0.00000000f }
};
// scipy.signal.butter(1, 300 / 8000.0, 'lowpass', analog=False)
// NOTE: Technically, order-1 filter, b[2] = a[2] = 0.
constexpr iir_biquad_config_t audio_16k_deemph_300_6_config {
{ 0.05568894f, 0.05568894f, 0.00000000f },
{ 1.00000000f, -0.88862213f, 0.00000000f }
};
// scipy.signal.butter(1, 300 / 4000.0, 'lowpass', analog=False)
// NOTE: Technically, order-1 filter, b[2] = a[2] = 0.
constexpr iir_biquad_config_t audio_8k_deemph_300_6_config {
{ 0.10583178f, 0.10583178f, 0.00000000f },
{ 1.00000000f, -0.78833643f, 0.00000000f }
};
// 75us RC time constant, used in broadcast FM in Americas, South Korea
// scipy.signal.butter(1, 2122 / 24000.0, 'lowpass', analog=False)
// NOTE: Technically, order-1 filter, b[2] = a[2] = 0.