Superminaren
/
MMDVM
mirror of https://github.com/g4klx/MMDVM.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Make whole FM chain RX level independant

This commit is contained in:
Geoffrey Merck 2020-05-08 09:01:00 +02:00
parent eb9c0dfd93
commit 77e0deee76
4 changed files with 14 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
FM.cpp
View File

@ -46,7 +46,8 @@ m_blanking(),
m_useCOS(true),
m_cosInvert(false),
m_rfAudioBoost(1U),
m_downsampler(128)//Size might need adjustement
m_downsampler(128),//Size might need adjustement
m_rxLevel(1)
{
}
@ -63,7 +64,8 @@ void CFM::samples(bool cos, q15_t* samples, uint8_t length)
uint8_t i = 0U;
for (; i < length; i++) {
q15_t currentSample = samples[i];//save to a local variable to avoid indirection on every access
// ARMv7-M has hardware integer division
q15_t currentSample = q15_t((q31_t(samples[i]) << 8) / m_rxLevel);
uint8_t ctcssState = m_ctcssRX.process(currentSample);
@ -188,7 +190,9 @@ uint8_t CFM::setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFreque
m_timeoutTone.setParams(timeoutLevel);
m_blanking.setParams(maxDev, timeoutLevel);
uint8_t ret = m_ctcssRX.setParams(ctcssFrequency, ctcssThreshold, rxLevel);
m_rxLevel = rxLevel; //q15_t(255)/q15_t(rxLevel >> 1);
uint8_t ret = m_ctcssRX.setParams(ctcssFrequency, ctcssThreshold);
if (ret != 0U)
return ret;
@ -438,3 +442,4 @@ void CFM::beginRelaying()
m_timeoutTimer.start();
m_ackMinTimer.start();
}

1
FM.h
View File

@ -84,6 +84,7 @@ private:
bool m_cosInvert;
q15_t m_rfAudioBoost;
CFMDownsampler m_downsampler;
q15_t m_rxLevel;
void stateMachine(bool validSignal);
void listeningState(bool validSignal);

23
FMCTCSSRX.cpp
View File

@ -86,15 +86,12 @@ m_threshold(0),
m_count(0U),
m_q0(0),
m_q1(0),
m_result(CTS_NONE),
m_rxLevelInverse(1)
m_result(CTS_NONE)
{
}
uint8_t CFMCTCSSRX::setParams(uint8_t frequency, uint8_t threshold, uint8_t level)
uint8_t CFMCTCSSRX::setParams(uint8_t frequency, uint8_t threshold)
{
m_rxLevelInverse = q15Division(65535, q15_t(level * 128));
m_coeffDivTwo = 0;
for (uint8_t i = 0U; i < CTCSS_TABLE_DATA_LEN; i++) {
@ -114,7 +111,8 @@ uint8_t CFMCTCSSRX::setParams(uint8_t frequency, uint8_t threshold, uint8_t leve
uint8_t CFMCTCSSRX::process(q15_t sample)
{
q31_t sample31 = q31_t(sample) * m_rxLevelInverse;
//get more dynamic into the decoder by multiplying the sample by 1.5
q31_t sample31 = q31_t(sample) + (q31_t(sample) >> 1);
m_result &= ~CTS_READY;
@ -174,16 +172,3 @@ void CFMCTCSSRX::reset()
m_result = CTS_NONE;
m_count = 0U;
}
//Taken from https://en.wikipedia.org/wiki/Q_(number_format)#Division
q15_t CFMCTCSSRX::q15Division(q15_t a, q15_t divisor)
{
q31_t a31 = q31_t(a) << 16;
if (((a >> 31) & 1) == ((divisor >> 15) & 1))
a31 += divisor >> 1;
else
a31 -= divisor >> 1;
return a31 / divisor;
}

5
FMCTCSSRX.h
View File

@ -34,7 +34,7 @@ class CFMCTCSSRX {
public:
CFMCTCSSRX();
uint8_t setParams(uint8_t frequency, uint8_t threshold, uint8_t level);
uint8_t setParams(uint8_t frequency, uint8_t threshold);
uint8_t process(q15_t sample);
@ -47,9 +47,6 @@ private:
q31_t m_q0;
q31_t m_q1;
uint8_t m_result;
q15_t m_rxLevelInverse;
q15_t q15Division(q15_t a, q15_t divisor);
};
#endif