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SSB demod: continuous sum for SSB downsampling

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f4exb 2015-12-26 04:04:22 +01:00
parent 332fe54b6a
commit 2b98bc9d8a
2 changed files with 8 additions and 6 deletions
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13
plugins/channel/ssb/ssbdemod.cpp
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@ -50,6 +50,7 @@ SSBDemod::SSBDemod(SampleSink* sampleSink) :
m_audioBuffer.resize(1<<9); m_audioBuffer.resize(1<<9);
m_audioBufferFill = 0; m_audioBufferFill = 0;
m_undersampleCount = 0; m_undersampleCount = 0;
m_sum = 0;
m_usb = true; m_usb = true;
m_magsq = 0.0f; m_magsq = 0.0f;
@ -83,7 +84,7 @@ void SSBDemod::configure(MessageQueue* messageQueue,
void SSBDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool positiveOnly) void SSBDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool positiveOnly)
{ {
Complex ci; Complex ci;
fftfilt::cmplx *sideband, sum; fftfilt::cmplx *sideband;
Real avg; Real avg;
int n_out; int n_out;
@ -113,18 +114,18 @@ void SSBDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
// Downsample by 2^(m_scaleLog2 - 1) for SSB band spectrum display // Downsample by 2^(m_scaleLog2 - 1) for SSB band spectrum display
// smart decimation with bit gain using float arithmetic (23 bits significand) // smart decimation with bit gain using float arithmetic (23 bits significand)
sum += sideband[i]; m_sum += sideband[i];
if (!(m_undersampleCount++ & decim_mask)) if (!(m_undersampleCount++ & decim_mask))
{ {
Real avgr = sum.real() / decim; Real avgr = m_sum.real() / decim;
Real avgi = sum.imag() / decim; Real avgi = m_sum.imag() / decim;
m_magsq = (avgr * avgr + avgi * avgi) / (1<<30); m_magsq = (avgr * avgr + avgi * avgi) / (1<<30);
//avg = (sum.real() + sum.imag()) * 0.7 * 32768.0 / decim; //avg = (sum.real() + sum.imag()) * 0.7 * 32768.0 / decim;
avg = (avgr + avgi) * 0.7; avg = (avgr + avgi) * 0.7;
m_sampleBuffer.push_back(Sample(avg, 0.0)); m_sampleBuffer.push_back(Sample(avg, 0.0));
sum.real() = 0.0; m_sum.real() = 0.0;
sum.imag() = 0.0; m_sum.imag() = 0.0;
} }
if (m_audioBinaual) if (m_audioBinaual)

1
plugins/channel/ssb/ssbdemod.h
View File

@ -112,6 +112,7 @@ private:
Real m_LowCutoff; Real m_LowCutoff;
Real m_volume; Real m_volume;
int m_spanLog2; int m_spanLog2;
fftfilt::cmplx m_sum;
int m_undersampleCount; int m_undersampleCount;
int m_sampleRate; int m_sampleRate;
int m_frequency; int m_frequency;