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96 seems to be the smallest sensible Hann winlength

pull/5/head
Oona 2013-01-19 18:19:01 +02:00
rodzic 4a787e492d
commit 692d5436da
2 zmienionych plików z 11 dodań i 13 usunięć
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2
fsk.c
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@ -22,7 +22,7 @@ void GetFSK (char *dest) {
guint FFTLen = 2048, i=0, LoBin, HiBin, MidBin, TestNum=0, TestPtr=0;
guchar Bit = 0, AsciiByte = 0, BytePtr = 0, TestBits[24] = {0}, BitPtr=0;
double HiPow,LoPow,Hann[970];
gboolean InSync = FALSE;
gboolean InSync = FALSE;
// Bit-reversion lookup table
static const guchar BitRev[] = {

22
video.c
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@ -40,8 +40,8 @@ gboolean GetVideo(guchar Mode, double Rate, int Skip, gboolean Redraw) {
guchar Channel = 0, WinIdx = 0;
// Initialize Hann windows of different lengths
gushort HannLens[7] = { 32, 64, 96, 128, 256, 512, 1024 };
for (j = 0; j < 7; j++)
gushort HannLens[5] = { 96, 128, 256, 512, 1024 };
for (j = 0; j < 5; j++)
for (i = 0; i < HannLens[j]; i++)
Hann[j][i] = 0.5 * (1 - cos( (2 * M_PI * i) / (HannLens[j] - 1)) );
@ -125,7 +125,7 @@ gboolean GetVideo(guchar Mode, double Rate, int Skip, gboolean Redraw) {
memset(out, 0, sizeof(out[0])*FFTLen);
// Hann window
for (i = 0; i < 64; i++) in[i] = pcm.Buffer[pcm.WindowPtr+i-32] / 32768.0 * Hann[1][i];
for (i = 0; i < 96; i++) in[i] = pcm.Buffer[pcm.WindowPtr+i-32] / 32768.0 * Hann[0][i];
fftw_execute(Plan1024);
@ -156,7 +156,7 @@ gboolean GetVideo(guchar Mode, double Rate, int Skip, gboolean Redraw) {
if (t >= NextSNRtime) {
// Apply Hann window
for (i = 0; i < FFTLen; i++) in[i] = pcm.Buffer[pcm.WindowPtr + i - FFTLen/2] / 32768.0 * Hann[6][i];
for (i = 0; i < FFTLen; i++) in[i] = pcm.Buffer[pcm.WindowPtr + i - FFTLen/2] / 32768.0 * Hann[4][i];
// FFT
fftw_execute(Plan1024);
@ -205,16 +205,14 @@ gboolean GetVideo(guchar Mode, double Rate, int Skip, gboolean Redraw) {
if (!Adaptive) WinIdx = 0;
else if (SNR >= 30) WinIdx = 0;
else if (SNR >= 10) WinIdx = 1;
else if (SNR >= 9) WinIdx = 2;
else if (SNR >= 3) WinIdx = 3;
else if (SNR >= -5) WinIdx = 4;
else if (SNR >= -10) WinIdx = 5;
else WinIdx = 6;
else if (SNR >= 9) WinIdx = 0;
else if (SNR >= 3) WinIdx = 1;
else if (SNR >= -5) WinIdx = 2;
else if (SNR >= -10) WinIdx = 3;
else WinIdx = 4;
// Minimum winlength can be doubled for Scottie DX
if (Mode == SDX && WinIdx < 6) WinIdx++;
if (Mode == SDX && WinIdx < 4) WinIdx++;
WinLength = HannLens[WinIdx];