VE7UWU/sdrangel
1
0
Fork 0
mirror of https://github.com/f4exb/sdrangel.git synced 2025-07-23 03:05:30 -04:00
Code Issues Projects Releases Wiki Activity

Implemented full SSB variable span with averaging in the SSB spectrum decimator

Browse Source
This commit is contained in:
f4exb 2015-06-12 02:23:07 +02:00
parent 85610c6a86
commit 7727ae7a36
2 changed files with 16 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
plugins/channel/ssb/ssbdemod.cpp
View File

@ -63,8 +63,11 @@ void SSBDemod::configure(MessageQueue* messageQueue, Real Bandwidth, Real LowCut
void SSBDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly) void SSBDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly)
{ {
Complex ci; Complex ci;
fftfilt::cmplx *sideband; fftfilt::cmplx *sideband, sum;
Real avg;
int n_out; int n_out;
int decim = 1<<(m_spanLog2 - 1);
unsigned char decim_mask = decim - 1; // counter LSB bit mask for decimation by 2^(m_scaleLog2 - 1)
for(SampleVector::const_iterator it = begin; it < end; ++it) { for(SampleVector::const_iterator it = begin; it < end; ++it) {
Complex c(it->real() / 32768.0, it->imag() / 32768.0); Complex c(it->real() / 32768.0, it->imag() / 32768.0);
@ -79,9 +82,17 @@ void SSBDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iter
for (int i = 0; i < n_out; i++) { for (int i = 0; i < n_out; i++) {
Real demod = (sideband[i].real() + sideband[i].imag()) * 0.7 * 32768.0; Real demod = (sideband[i].real() + sideband[i].imag()) * 0.7 * 32768.0;
// Downsample by 4x for audio display // Downsample by 2^(m_scaleLog2 - 1) for SSB band spectrum display
if (!(m_undersampleCount++ & 3)) // smart decimation with bit gain using float arithmetic (23 bits significand)
m_sampleBuffer.push_back(Sample(demod, 0.0));
sum += sideband[i];
if (!(m_undersampleCount++ & decim_mask)) {
avg = (sum.real() + sum.imag()) * 0.7 * 32768.0 / decim;
m_sampleBuffer.push_back(Sample(avg, 0.0));
sum.real() = 0.0;
sum.imag() = 0.0;
}
qint16 sample = (qint16)(demod * m_volume * 10); qint16 sample = (qint16)(demod * m_volume * 10);
m_audioBuffer[m_audioBufferFill].l = sample; m_audioBuffer[m_audioBufferFill].l = sample;

2
plugins/channel/ssb/ssbdemodgui.cpp
View File

@ -261,7 +261,7 @@ SSBDemodGUI::~SSBDemodGUI()
bool SSBDemodGUI::setNewRate(int spanLog2) bool SSBDemodGUI::setNewRate(int spanLog2)
{ {
if ((spanLog2 < 0) || (spanLog2 > 5)) { if ((spanLog2 < 1) || (spanLog2 > 5)) {
return false; return false;
} }