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calculate signal periods

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This commit is contained in:
merlokk 2022-06-27 01:03:13 +03:00
parent 2248eadc7f
commit a58c5b57ba
1 changed files with 63 additions and 3 deletions
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64
client/src/cmdhftexkom.c
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@ -38,7 +38,7 @@ inline uint32_t GetGraphBuffer(uint32_t indx) {
return g_GraphBuffer[indx] + 128;
}
static uint32_t TexkomSearchStart(uint32_t indx, uint8_t threshold) {
static uint32_t TexkomSearchStart(uint32_t indx, uint32_t threshold) {
// one bit length = 27, minimal noise = 60
uint32_t lownoisectr = 0;
for (uint32_t i = indx; i < g_GraphTraceLen; i++) {
@ -56,6 +56,26 @@ static uint32_t TexkomSearchStart(uint32_t indx, uint8_t threshold) {
return 0;
}
static uint32_t TexkomSearchLength(uint32_t indx, uint32_t threshold) {
// one bit length = 27, minimal noise = 60
uint32_t lownoisectr = 0;
uint32_t datalen = 0;
for (uint32_t i = indx; i < g_GraphTraceLen; i++) {
if (lownoisectr > 60) {
break;
} else {
if (GetGraphBuffer(i) > threshold) {
lownoisectr = 0;
datalen = i - indx + 27;
} else {
lownoisectr++;
}
}
}
return datalen;
}
static uint32_t TexkomSearchMax(uint32_t indx, uint32_t len) {
uint32_t res = 0;
@ -70,6 +90,22 @@ static uint32_t TexkomSearchMax(uint32_t indx, uint32_t len) {
return res;
}
static bool TexkomCorrelate(uint32_t indx, uint32_t threshold) {
if (indx < 2 || indx + 2 > g_GraphTraceLen)
return false;
uint32_t g1 = GetGraphBuffer(indx - 2);
uint32_t g2 = GetGraphBuffer(indx - 1);
uint32_t g3 = GetGraphBuffer(indx);
uint32_t g4 = GetGraphBuffer(indx + 1);
uint32_t g5 = GetGraphBuffer(indx + 2);
return (
(g3 > threshold) &&
(g3 >= g2) && (g3 >= g1) && (g3 > g4) && (g3 > g5)
);
}
static int CmdHFTexkomReader(const char *Cmd) {
CLIParserContext *ctx;
CLIParserInit(&ctx, "hf texkom reader",
@ -107,14 +143,38 @@ static int CmdHFTexkomReader(const char *Cmd) {
if (sindx == 0 || sindx > samplesCount - 5)
break;
uint32_t slen = TexkomSearchLength(sindx, TEXKOM_NOISE_THRESHOLD);
if (slen == 0)
continue;
uint32_t maxlvl = TexkomSearchMax(sindx, 1760);
if (maxlvl < TEXKOM_NOISE_THRESHOLD) {
sindx += 1700;
continue;
}
PrintAndLogEx(WARNING, "--- indx: %d, max: %d", sindx, maxlvl);
uint32_t noiselvl = maxlvl / 5;
if (noiselvl < TEXKOM_NOISE_THRESHOLD)
noiselvl = TEXKOM_NOISE_THRESHOLD;
PrintAndLogEx(WARNING, "--- indx: %d, len: %d, max: %d, noise: %d", sindx, slen, maxlvl, noiselvl);
uint32_t implengths[256] = {};
uint32_t implengthslen = 0;
uint32_t impulseindx = 0;
uint32_t impulsecnt = 0;
for (uint32_t i = 0; i < slen; i++) {
if (TexkomCorrelate(sindx + i, noiselvl)) {
impulsecnt++;
if (impulseindx != 0) {
if (implengthslen < 256)
implengths[implengthslen++] = sindx + i - impulseindx;
}
impulseindx = sindx + i;
}
}
PrintAndLogEx(WARNING, "--- impulses: %d, lenarray: %d, [%d,%d]", impulsecnt, implengthslen, implengths[0], implengths[1]);
}