VE7UWU/sdrangel
1
0
Fork 0
mirror of https://github.com/f4exb/sdrangel.git synced 2026-06-02 06:04:39 -04:00
Code Issues Projects Releases Wiki Activity

Offset tuning.

Browse Source
This commit is contained in:
Hexameron
2014-05-18 17:04:24 +01:00
parent 7d3bfb26fc
commit fbef672cd0
4 changed files with 85 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files
plugins/samplesource/rtlsdr/rtlsdrthread.cpp
+78 -5
View File
@@ -28,7 +28,7 @@ RTLSDRThread::RTLSDRThread(rtlsdr_dev_t* dev, SampleFifo* sampleFifo, QObject* p
m_dev(dev),
m_convertBuffer(BLOCKSIZE),
m_sampleFifo(sampleFifo),
m_decimation(1)
m_decimation(2)
{
}
@@ -74,6 +74,8 @@ void RTLSDRThread::run()
m_running = false;
}
#if 0
void RTLSDRThread::decimate2(SampleVector::iterator* it, const quint8* buf, qint32 len)
{
for(int pos = 0; pos < len; pos += 2) {
@@ -130,18 +132,89 @@ void RTLSDRThread::decimate16(SampleVector::iterator* it, const quint8* buf, qin
}
}
#else
void RTLSDRThread::decimate2(SampleVector::iterator* it, const quint8* buf, qint32 len)
{
qint16 xreal, yimag;
for (int pos = 0; pos < len + 7; pos += 8) {
xreal = buf[pos+0] - buf[pos+3];
yimag = buf[pos+1] + buf[pos+2] - 255;
Sample s( xreal << 5, yimag << 5 );
**it = s;
(*it)++;
xreal = buf[pos+7] - buf[pos+4];
yimag = 255 - buf[pos+5] - buf[pos+6];
Sample t( xreal << 5, yimag << 5 );
**it = t;
(*it)++;
}
}
void RTLSDRThread::decimate4(SampleVector::iterator* it, const quint8* buf, qint32 len)
{
qint16 xreal, yimag;
for (int pos = 0; pos < len + 7; pos += 8) {
xreal = buf[pos+0] - buf[pos+3] + buf[pos+7] - buf[pos+4];
yimag = buf[pos+1] - buf[pos+5] + buf[pos+2] - buf[pos+6];
Sample s( xreal << 5, yimag << 5 );
**it = s;
(*it)++;
}
}
void RTLSDRThread::decimate8(SampleVector::iterator* it, const quint8* buf, qint32 len)
{
qint16 xreal, yimag;
for (int pos = 0; pos < len + 15; pos += 8) {
xreal = buf[pos+0] - buf[pos+3] + buf[pos+7] - buf[pos+4];
yimag = buf[pos+1] - buf[pos+5] + buf[pos+2] - buf[pos+6];
pos += 8;
xreal += buf[pos+0] - buf[pos+3] + buf[pos+7] - buf[pos+4];
yimag += buf[pos+1] - buf[pos+5] + buf[pos+2] - buf[pos+6];
Sample s( xreal << 4, yimag << 4 );
**it = s;
(*it)++;
}
}
void RTLSDRThread::decimate16(SampleVector::iterator* it, const quint8* buf, qint32 len)
{
// Offset tuning: 4x downsample and rotate, then
// downsample 4x more. [ rotate: 0, 1, -3, 2, -4, -5, 7, -6]
qint16 xreal, yimag;
for (int step = 0; step < len - 31; step +=32) {
xreal = yimag = 0;
for (int pos = step; pos < step + 32; pos += 8) {
xreal += buf[pos+0] - buf[pos+3] + buf[pos+7] - buf[pos+4];
yimag += buf[pos+1] - buf[pos+5] + buf[pos+2] - buf[pos+6];
}
Sample s( xreal << 4, yimag << 4 );
**it = s;
(*it)++;
}
}
#endif
void RTLSDRThread::callback(const quint8* buf, qint32 len)
{
qint16 xreal, yimag, phase;
SampleVector::iterator it = m_convertBuffer.begin();
switch(m_decimation) {
case 0: // 1:1 = no decimation
for(int pos = 0; pos < len; pos += 2) {
*it = Sample((((qint8)buf[pos]) - 128) << 8, (((qint8)buf[pos + 1]) - 128) << 8);
++it;
// just rotation
phase = -1;
for (int pos = 0; pos < len + 3; pos += 4) {
phase *= -1;
xreal = phase * (buf[pos+0] - 127);
yimag = phase * (buf[pos+1] - 127);
*it++ = Sample( xreal<<6,yimag<<6);
xreal = phase * (128 - buf[pos+3]);
yimag = phase * (buf[pos+2] - 127);
*it++ = Sample( xreal<<6,yimag<<6);
}
break;
case 1: // 1:2
decimate2(&it, buf, len);
break;