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Revert the CTCSS decoder to floats.

This commit is contained in:
Jonathan Naylor 2020-04-19 21:21:10 +01:00
parent a310bf0547
commit 1aef1a39f2
2 changed files with 74 additions and 98 deletions
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162
FMCTCSSRX.cpp
View File

@ -21,64 +21,59 @@
#include "FMCTCSSRX.h" #include "FMCTCSSRX.h"
const struct CTCSS_TABLE { const struct CTCSS_TABLE {
uint8_t frequency; uint8_t frequency;
q31_t coeff; float32_t coeff;
} CTCSS_TABLE_DATA[] = { } CTCSS_TABLE_DATA[] = {
{67, 65527}, { 67U, 1.999692F},
{69, 65526}, { 69U, 1.999671F},
{71, 65525}, { 71U, 1.999646F},
{74, 65524}, { 74U, 1.999621F},
{77, 65523}, { 77U, 1.999594F},
{79, 65522}, { 79U, 1.999565F},
{82, 65521}, { 82U, 1.999534F},
{85, 65520}, { 85U, 1.999500F},
{88, 65519}, { 88U, 1.999463F},
{91, 65518}, { 91U, 1.999426F},
{94, 65517}, { 94U, 1.999384F},
{97, 65516}, { 97U, 1.999350F},
{100, 65514}, {100U, 1.999315F},
{103, 65513}, {103U, 1.999266F},
{107, 65511}, {107U, 1.999212F},
{110, 65509}, {110U, 1.999157F},
{114, 65507}, {114U, 1.999097F},
{123, 65503}, {118U, 1.999033F},
{127, 65501}, {123U, 1.998963F},
{131, 65498}, {127U, 1.998889F},
{136, 65495}, {131U, 1.998810F},
{141, 65492}, {136U, 1.998723F},
{146, 65489}, {141U, 1.998632F},
{150, 65487}, {146U, 1.998535F},
{151, 65486}, {151U, 1.998429F},
{156, 65482}, {156U, 1.998317F},
{159, 65480}, {159U, 1.998250F},
{162, 65478}, {162U, 1.998197F},
{165, 65476}, {165U, 1.998123F},
{167, 65474}, {167U, 1.998068F},
{171, 65472}, {171U, 1.997989F},
{173, 65470}, {173U, 1.997930F},
{177, 65467}, {177U, 1.997846F},
{179, 65465}, {179U, 1.997782F},
{183, 65462}, {183U, 1.997693F},
{186, 65460}, {186U, 1.997624F},
{188, 65458}, {189U, 1.997529F},
{189, 65457}, {192U, 1.997453F},
{192, 65454}, {196U, 1.997351F},
{196, 65451}, {199U, 1.997273F},
{199, 65448}, {203U, 1.997162F},
{203, 65445}, {206U, 1.997078F},
{206, 65442}, {210U, 1.996958F},
{210, 65438}, {218U, 1.996741F},
{213, 65435}, {225U, 1.996510F},
{218, 65431}, {229U, 1.996404F},
{221, 65428}, {233U, 1.996261F},
{225, 65424}, {241U, 1.995994F},
{229, 65420}, {250U, 1.995708F},
{233, 65416}, {254U, 1.995576F}};
{237, 65412},
{241, 65407},
{245, 65403},
{250, 65398},
{254, 65393}};
const uint8_t CTCSS_TABLE_DATA_LEN = 50U; const uint8_t CTCSS_TABLE_DATA_LEN = 50U;
@ -86,11 +81,11 @@ const uint8_t CTCSS_TABLE_DATA_LEN = 50U;
const uint16_t N = 24000U / 4U; const uint16_t N = 24000U / 4U;
CFMCTCSSRX::CFMCTCSSRX() : CFMCTCSSRX::CFMCTCSSRX() :
m_coeff(0), m_coeff(0.0F),
m_threshold(0U), m_threshold(0.0F),
m_count(0U), m_count(0U),
m_q0(0), m_q0(0.0F),
m_q1(0), m_q1(0.0F),
m_result(false) m_result(false)
{ {
} }
@ -104,50 +99,31 @@ uint8_t CFMCTCSSRX::setParams(uint8_t frequency, uint8_t threshold)
} }
} }
if (m_coeff == 0) if (m_coeff == 0.0F)
return 4U; return 4U;
m_threshold = threshold * threshold; m_threshold = float32_t(threshold * threshold);
return 0U; return 0U;
} }
bool CFMCTCSSRX::process(const q15_t* samples, uint8_t length) bool CFMCTCSSRX::process(q15_t* samples, uint8_t length)
{ {
float32_t data[RX_BLOCK_SIZE];
::arm_q15_to_float(samples, data, length);
for (unsigned int i = 0U; i < length; i++) { for (unsigned int i = 0U; i < length; i++) {
q31_t q2 = m_q1; float32_t q2 = m_q1;
m_q1 = m_q0; m_q1 = m_q0;
m_q0 = m_coeff * m_q1 - q2 + data[i];
// Q31 multiplication, t2 = m_coeff * m_q1
q63_t t1 = m_coeff * m_q1;
q31_t t2 = __SSAT(t1 >> 32, 31);
// m_q0 = m_coeff * m_q1 - q2 + samples[i]
m_q0 = t2 - q2 + samples[i];
m_count++; m_count++;
if (m_count == N) { if (m_count == N) {
// Q31 multiplication, t2 = m_q0 * m_q0 float32_t value = m_q0 * m_q0 + m_q1 * m_q1 - m_q0 * m_q1 * m_coeff;
q63_t t1 = m_q0 * m_q0;
q31_t t2 = __SSAT(t1 >> 32, 31);
// Q31 multiplication, t4 = m_q0 * m_q0
q63_t t3 = m_q1 * m_q1;
q31_t t4 = __SSAT(t3 >> 32, 31);
// Q31 multiplication, t8 = m_q0 * m_q1 * m_coeff
q63_t t5 = m_q0 * m_q1;
q31_t t6 = __SSAT(t5 >> 32, 31);
q63_t t7 = t6 * m_coeff;
q31_t t8 = __SSAT(t7 >> 32, 31);
// value = m_q0 * m_q0 + m_q1 * m_q1 - m_q0 * m_q1 * m_coeff
q31_t value = t2 + t4 - t8;
m_result = value >= m_threshold; m_result = value >= m_threshold;
m_count = 0U; m_count = 0U;
m_q0 = 0; m_q0 = 0.0F;
m_q1 = 0; m_q1 = 0.0F;
} }
} }
@ -156,8 +132,8 @@ bool CFMCTCSSRX::process(const q15_t* samples, uint8_t length)
void CFMCTCSSRX::reset() void CFMCTCSSRX::reset()
{ {
m_q0 = 0; m_q0 = 0.0F;
m_q1 = 0; m_q1 = 0.0F;
m_result = false; m_result = false;
m_count = 0U; m_count = 0U;
} }

10
FMCTCSSRX.h
View File

@ -27,16 +27,16 @@ public:
uint8_t setParams(uint8_t frequency, uint8_t threshold); uint8_t setParams(uint8_t frequency, uint8_t threshold);
bool process(const q15_t* samples, uint8_t length); bool process(q15_t* samples, uint8_t length);
void reset(); void reset();
private: private:
q31_t m_coeff; float32_t m_coeff;
uint16_t m_threshold; float32_t m_threshold;
uint16_t m_count; uint16_t m_count;
q31_t m_q0; float32_t m_q0;
q31_t m_q1; float32_t m_q1;
bool m_result; bool m_result;
}; };