VE7UWU
/
sdrangel
mirror of https://github.com/f4exb/sdrangel.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Implemented CTCSS detection in the NFM demod. No GUI for the moment just logs to stderr

This commit is contained in:
f4exb 2015-06-16 08:15:28 +02:00
parent 40f00c0ed7
commit 471364f540
2 changed files with 28 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
plugins/channel/nfm/nfmdemod.cpp
View File

@ -23,9 +23,12 @@
#include "dsp/dspcommands.h"
#include "dsp/pidcontroller.h"
#include <iostream>
MESSAGE_CLASS_DEFINITION(NFMDemod::MsgConfigureNFMDemod, Message)
NFMDemod::NFMDemod(AudioFifo* audioFifo, SampleSink* sampleSink) :
m_sampleCount(0),
m_sampleSink(sampleSink),
m_audioFifo(audioFifo)
{
@ -45,6 +48,8 @@ NFMDemod::NFMDemod(AudioFifo* audioFifo, SampleSink* sampleSink) :
m_movingAverage.resize(16, 0);
m_agcLevel = 0.003;
m_AGC.resize(4096, m_agcLevel, 0, 0.1*m_agcLevel);
m_ctcssDetector.setCoefficients(1200, 6000.0); // 0.2s detection rate
}
NFMDemod::~NFMDemod()
@ -144,13 +149,30 @@ void NFMDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iter
m_m2Sample = m_m1Sample;
m_m1Sample = ci;
m_sampleCount++;
// AF processing
//demod = m_lowpass.filter(demod);
//sample = demod * 32700;
Real ctcss_sample = m_lowpass.filter(demod);
if ((m_sampleCount & 7) == 7) // decimate 48k -> 6k
{
if (m_ctcssDetector.analyze(&ctcss_sample))
{
int maxToneIndex;
if (m_ctcssDetector.getDetectedTone(maxToneIndex))
{
std::cerr << "CTCSS tone detected: " << m_ctcssDetector.getToneSet()[maxToneIndex] << std::endl;
}
}
}
demod = m_bandpass.filter(demod);
demod *= m_running.m_volume;
//sample = demod * 32700;
sample = demod * ((1<<16)/301); // denominator = bandpass filter number of taps
} else {
@ -239,7 +261,7 @@ void NFMDemod::apply()
if((m_config.m_afBandwidth != m_running.m_afBandwidth) ||
(m_config.m_audioSampleRate != m_running.m_audioSampleRate)) {
//m_lowpass.create(21, m_config.m_audioSampleRate, m_config.m_afBandwidth);
m_lowpass.create(301, m_config.m_audioSampleRate, 250.0);
m_bandpass.create(301, m_config.m_audioSampleRate, 300.0, m_config.m_afBandwidth);
}

5
plugins/channel/nfm/nfmdemod.h
View File

@ -26,6 +26,7 @@
#include "dsp/bandpass.h"
#include "dsp/movingaverage.h"
#include "dsp/agc.h"
#include "dsp/ctcssdetector.h"
#include "audio/audiofifo.h"
#include "util/message.h"
@ -112,8 +113,10 @@ private:
Interpolator m_interpolator;
Real m_interpolatorDistance;
Real m_interpolatorDistanceRemain;
//Lowpass<Real> m_lowpass;
Lowpass<Real> m_lowpass;
Bandpass<Real> m_bandpass;
CTCSSDetector m_ctcssDetector;
int m_sampleCount;
Real m_squelchLevel;
int m_squelchState;