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chg: use signal mean instead of hardcoded FSK_PSK_THRESHOLD

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chg: stricter clock identification
chg: askclock detection, trying to find a better starting point
This commit is contained in:
Chris 2018-11-02 18:38:06 +01:00
parent d30454fc5a
commit b9676e6c93
2 changed files with 43 additions and 31 deletions
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72
common/lfdemod.c
View file

@ -320,14 +320,14 @@ size_t findModStart(uint8_t *src, size_t size, uint8_t expWaveSize) {
size_t i = 0;
size_t waveSizeCnt = 0;
uint8_t thresholdCnt = 0;
bool isAboveThreshold = src[i++] >= FSK_PSK_THRESHOLD;
bool isAboveThreshold = src[i++] >= signalprop.mean; //FSK_PSK_THRESHOLD;
for (; i < size-20; i++ ) {
if(src[i] < FSK_PSK_THRESHOLD && isAboveThreshold) {
if(src[i] < signalprop.mean && isAboveThreshold) {
thresholdCnt++;
if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
isAboveThreshold = false;
waveSizeCnt = 0;
} else if (src[i] >= FSK_PSK_THRESHOLD && !isAboveThreshold) {
} else if (src[i] >= signalprop.mean && !isAboveThreshold) {
thresholdCnt++;
if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
isAboveThreshold = true;
@ -337,15 +337,24 @@ size_t findModStart(uint8_t *src, size_t size, uint8_t expWaveSize) {
}
if (thresholdCnt > 10) break;
}
if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u", i, thresholdCnt);
if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at index %u, count: %u", i, thresholdCnt);
return i;
}
// iceman: ranges the old defintion, becomes very forgiving when clock speed increase.
// clocks[i] - (clocks[i]/8) && testclk <= clocks[i]+1 )
// 8 (7-9)
// 16 (14-17)
// 32 (28-33)
// 40 (35-41)
// 50 (46-51)
// 64 (56-65)
// 128 (112-129)
int getClosestClock(int testclk) {
uint8_t clocks[] = {8,16,32,40,50,64,128};
for (uint8_t i = 0; i < 7; i++)
if ( testclk >= clocks[i] - (clocks[i]/8) && testclk <= clocks[i]+1 )
if ( testclk >= clocks[i]-2 && testclk <= clocks[i]+1 )
return clocks[i];
return 0;
@ -474,7 +483,7 @@ int ManchesterEncode(uint8_t *bits, size_t size) {
// by marshmellow
// to detect a wave that has heavily clipped (clean) samples
// loop 512 samples, if 300 of them is deemed maxed out, we assume the wave is clipped.
// loop 512 samples, if 250 of them is deemed maxed out, we assume the wave is clipped.
bool DetectCleanAskWave(uint8_t *dest, size_t size, uint8_t high, uint8_t low) {
bool allArePeaks = true;
uint16_t cntPeaks = 0;
@ -516,8 +525,8 @@ int DetectStrongAskClock(uint8_t *dest, size_t size, int high, int low, int *clo
getNextHigh(dest, size, high, &i);
getNextLow(dest, size, low, &i);
// loop through all samples
while (i < size) {
// loop through all samples (well, we don't want to go out-of-bounds)
while (i < size-512) {
// measure from low to low
startwave = i;
@ -562,36 +571,35 @@ int DetectASKClock(uint8_t *dest, size_t size, int *clock, int maxErr) {
// just noise - no super good detection. good enough
if (signalprop.isnoise) {
if (g_debugMode == 2) prnt("DEBUG DetectASKClock: just noise detected - quitting");
if (g_debugMode == 2) prnt("DEBUG DetectASKClock: just noise detected - aborting");
return -1;
}
//get high and low peak
int peak_hi, peak_low;
//getHiLo(dest, loopCnt, &peak_hi, &peak_low, 75, 75);
getHiLo(&peak_hi, &peak_low, 75, 75);
//test for large clean peaks
if (!clockFnd){
if (DetectCleanAskWave(dest, size, peak_hi, peak_low)){
int ans = DetectStrongAskClock(dest, size, peak_hi, peak_low, clock);
if (g_debugMode == 2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i", *clock ,ans);
if (ans > 0){
return ans; //return shortest wave start position
}
int idx = DetectStrongAskClock(dest, size, peak_hi, peak_low, clock);
if (g_debugMode == 2)
prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, Best Starting Position: %i", *clock, idx);
if (idx > 0)
return idx; //return shortest wave start position
}
}
// test clock if given as cmd parameter
if ( *clock > 0 )
clk[0] = *clock;
uint16_t ii;
uint8_t clkCnt, tol = 0;
size_t j = 0;
uint16_t bestErr[] = {1000,1000,1000,1000,1000,1000,1000,1000,1000};
uint8_t bestStart[] = {0,0,0,0,0,0,0,0,0};
size_t errCnt = 0;
size_t arrLoc, loopEnd;
size_t errCnt = 0, arrLoc, loopEnd;
if (clockFnd > 0) {
clkCnt = clockFnd;
@ -614,14 +622,17 @@ int DetectASKClock(uint8_t *dest, size_t size, int *clock, int maxErr) {
bestErr[clkCnt] = 1000;
//try lining up the peaks by moving starting point (try first few clocks)
for (ii=0; ii < loopCnt; ii++){
if (dest[ii] < peak_hi && dest[ii] > peak_low) continue;
// get to first full low to prime loop and skip incomplete first pulse
getNextHigh(dest, size, peak_hi, &j);
getNextLow(dest, size, peak_low, &j);
for (; j < loopCnt; j++){
errCnt = 0;
// now that we have the first one lined up test rest of wave array
loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
loopEnd = ((size-j-tol) / clk[clkCnt]) - 1;
for (i=0; i < loopEnd; ++i){
arrLoc = ii + (i * clk[clkCnt]);
arrLoc = j + (i * clk[clkCnt]);
if (dest[arrLoc] >= peak_hi || dest[arrLoc] <= peak_low){
} else if (dest[arrLoc-tol] >= peak_hi || dest[arrLoc-tol] <= peak_low){
} else if (dest[arrLoc+tol] >= peak_hi || dest[arrLoc+tol] <= peak_low){
@ -631,21 +642,22 @@ int DetectASKClock(uint8_t *dest, size_t size, int *clock, int maxErr) {
}
//if we found no errors then we can stop here and a low clock (common clocks)
// this is correct one - return this clock
//if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
//if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, j, i);
if (errCnt == 0 && clkCnt < 7) {
if (!clockFnd)
*clock = clk[clkCnt];
return ii;
return j;
}
//if we found errors see if it is lowest so far and save it as best run
if (errCnt < bestErr[clkCnt]) {
bestErr[clkCnt] = errCnt;
bestStart[clkCnt] = ii;
bestStart[clkCnt] = j;
}
}
}
uint8_t k;
uint8_t best = 0;
uint8_t k, best = 0;
for (k=1; k < clkEnd; ++k){
if (bestErr[k] < bestErr[best]){
if (bestErr[k] == 0) bestErr[k] = 1;
@ -1486,7 +1498,7 @@ int askdemod_ext(uint8_t *bits, size_t *size, int *clk, int *invert, int maxErr,
// just noise - no super good detection. good enough
if (signalprop.isnoise) {
if (g_debugMode == 2) prnt("DEBUG askdemod_ext: just noise detected - quitting");
if (g_debugMode == 2) prnt("DEBUG askdemod_ext: just noise detected - aborting");
return -2;
}
@ -1636,7 +1648,7 @@ size_t fsk_wave_demod(uint8_t *dest, size_t size, uint8_t fchigh, uint8_t fclow,
//find start of modulating data in trace
idx = findModStart(dest, size, fchigh);
// Need to threshold first sample
dest[0] = (dest[idx] < FSK_PSK_THRESHOLD) ? 0 : 1;
dest[0] = (dest[idx] < signalprop.mean) ? 0 : 1;
last_transition = idx;
idx++;
@ -1674,7 +1686,7 @@ size_t fsk_wave_demod(uint8_t *dest, size_t size, uint8_t fchigh, uint8_t fclow,
for(; idx < size-20; idx++) {
// threshold current value
dest[idx] = (dest[idx] < FSK_PSK_THRESHOLD) ? 0 : 1;
dest[idx] = (dest[idx] < signalprop.mean) ? 0 : 1;
// Check for 0->1 transition
if (dest[idx-1] < dest[idx]) {

2
common/lfdemod.h
View file

@ -19,7 +19,7 @@
#include <stdlib.h> // for
#include <stdbool.h> // for bool
#include "parity.h" // for parity test
#include "util.h" // for ARRAYLEN
//generic
typedef struct {
int low;