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SoftFM
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Reduce IF bandwidth to 100 kHz.

This commit is contained in:
Joris van Rantwijk 2013-12-29 18:50:56 +01:00
parent c3778fb920
commit f0d58eac10
3 changed files with 6 additions and 7 deletions
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2
Filter.cc
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@ -276,7 +276,7 @@ void LowPassFilterRC::process(const SampleVector& samples_in,
* H(s) = 1 / (1 - s * timeconst)
*
* Discrete domain:
* H(z) = (1 - exp(-1/timeconst)) / (1 - exp(-1/timeconst) / z)a
* H(z) = (1 - exp(-1/timeconst)) / (1 - exp(-1/timeconst) / z)
*/
Sample a1 = - exp(-1/m_timeconst);;
Sample b0 = 1 + a1;

8
FmDecode.h
View File

@ -72,10 +72,10 @@ private:
class FmDecoder
{
public:
static constexpr double default_deemphasis = 50;
static constexpr double default_bandwidth_if = 115000;
static constexpr double default_freq_dev = 75000;
static constexpr double default_bandwidth_pcm = 15000;
static constexpr double default_deemphasis = 50;
static constexpr double default_bandwidth_if = 100000;
static constexpr double default_freq_dev = 75000;
static constexpr double default_bandwidth_pcm = 15000;
/**
* Construct FM decoder.

3
main.cc
View File

@ -478,7 +478,6 @@ int main(int argc, char **argv)
adjust_gain(audiosamples, 0.5);
// TODO : investigate I/Q imbalance to fix Radio4 noise
// TODO : investigate if PLL receiver is better than phase discriminator at weak reception
// TODO : show mono/stereo (switching)
@ -523,7 +522,7 @@ int main(int argc, char **argv)
output_thread.join();
}
// TODO : cleanup
// No cleanup needed; everything handled by destructors.
return 0;
}