diff options
author | Andreas Eversberg <jolly@eversberg.eu> | 2017-05-17 14:11:48 +0200 |
---|---|---|
committer | Andreas Eversberg <jolly@eversberg.eu> | 2017-05-17 20:06:46 +0200 |
commit | 683078a7a01903c9bcbac196148f132fc00be6ad (patch) | |
tree | 6b7ed30577a3984fe68953014e755cf7641a8b3a | |
parent | ef7ff26793b290d5ee3725a5490f6e5bfeb7b5da (diff) |
SDR: Spectrum display will not scale FFT result
Instead the greatest possible width that will fit into the window will
be used. This width is 2 to the power of N.
-rw-r--r-- | src/common/display.h | 2 | ||||
-rw-r--r-- | src/common/display_spectrum.c | 134 |
2 files changed, 62 insertions, 74 deletions
diff --git a/src/common/display.h b/src/common/display.h index 59b1b4c..9f476de 100644 --- a/src/common/display.h +++ b/src/common/display.h @@ -19,7 +19,7 @@ typedef struct display_iq { float buffer[MAX_DISPLAY_IQ * 2]; } dispiq_t; -#define MAX_DISPLAY_SPECTRUM 256 +#define MAX_DISPLAY_SPECTRUM 1024 typedef struct display_spectrum { int interval_pos; diff --git a/src/common/display_spectrum.c b/src/common/display_spectrum.c index fcdd706..ef5e577 100644 --- a/src/common/display_spectrum.c +++ b/src/common/display_spectrum.c @@ -94,19 +94,33 @@ void display_spectrum(float *samples, int length) int pos, max; double *buffer_I, *buffer_Q; int color = 9; /* default color */ - int i, j, k, count; - int m; - double I, Q, v, c; + int i, j, k, o; + double I, Q, v; int s, e; if (!spectrum_on) return; get_win_size(&width, &h); - if (width > MAX_DISPLAY_SPECTRUM) - width = MAX_DISPLAY_SPECTRUM; + if (width > MAX_DISPLAY_WIDTH) + width = MAX_DISPLAY_WIDTH; + + /* calculate size of FFT */ + int m, fft_size = 0, fft_taps = 0; + for (m = 0; m < 16; m++) { + if ((1 << m) > MAX_DISPLAY_SPECTRUM) + break; + if ((1 << m) <= width) { + fft_taps = m; + fft_size = 1 << m; + } + } + if (m == 16) { + fprintf(stderr, "Size of spectrum is not a power of 2, please fix!\n"); + abort(); + } - int heigh[width], low[width]; + int heigh[fft_size], low[fft_size]; pos = disp.interval_pos; max = disp.interval_max; @@ -114,7 +128,7 @@ void display_spectrum(float *samples, int length) buffer_Q = disp.buffer_Q; for (i = 0; i < length; i++) { - if (pos >= MAX_DISPLAY_SPECTRUM) { + if (pos >= fft_size) { if (++pos == max) pos = 0; continue; @@ -122,106 +136,80 @@ void display_spectrum(float *samples, int length) buffer_I[pos] = samples[i * 2]; buffer_Q[pos] = samples[i * 2 + 1]; pos++; - if (pos == MAX_DISPLAY_SPECTRUM) { - /* calculate number of taps */ - for (m = 0; m < 16; m++) { - if ((1 << m) == MAX_DISPLAY_SPECTRUM) - break; - } - if (m == 16) { - fprintf(stderr, "Size of spectrum is not a power of 2, please fix!\n"); - abort(); - } - fft_process(1, m, buffer_I, buffer_Q); - count = 0; - c = 0.0; + if (pos == fft_size) { + fft_process(1, fft_taps, buffer_I, buffer_Q); k = 0; - for (j = 0; j < MAX_DISPLAY_SPECTRUM; j++) { + for (j = 0; j < fft_size; j++) { /* scale result vertically */ - I = buffer_I[(j + MAX_DISPLAY_SPECTRUM / 2) % MAX_DISPLAY_SPECTRUM]; - Q = buffer_Q[(j + MAX_DISPLAY_SPECTRUM / 2) % MAX_DISPLAY_SPECTRUM]; + I = buffer_I[(j + fft_size / 2) % fft_size]; + Q = buffer_Q[(j + fft_size / 2) % fft_size]; v = sqrt(I*I + Q*Q); v = log10(v) * 20 + db; if (v < 0) v = 0; v /= db; - /* scale down result horizontally by combining values */ - if (v > c) - c = v; buffer_max[j] -= DISPLAY_INTERVAL / 10.0; - if (c > buffer_max[j]) - buffer_max[j] = c; - count += width; - while (count >= MAX_DISPLAY_SPECTRUM) { - if (k >= width) { - fprintf(stderr, "Too many output values, please fix!\n"); - abort(); - } - /* heigh is the maximum value */ - heigh[k] = (double)(HEIGHT * 2 - 1) * (1.0 - buffer_max[j]); - if (heigh[k] < 0) - heigh[k] = 0; - if (heigh[k] >= (HEIGHT * 2)) - heigh[k] = (HEIGHT * 2) - 1; - /* low is the current value */ - low[k] = (double)(HEIGHT * 2 - 1) * (1.0 - c); - if (low[k] < 0) - low[k] = 0; - if (low[k] >= (HEIGHT * 2)) - low[k] = (HEIGHT * 2) - 1; - k++; - c = 0.0; - count -= MAX_DISPLAY_SPECTRUM; - } - } - if (k != width) { - fprintf(stderr, "k must be %d but is %d, please fix!\n", width, k); - abort(); + if (v > buffer_max[j]) + buffer_max[j] = v; + + /* heigh is the maximum value */ + heigh[j] = (double)(HEIGHT * 2 - 1) * (1.0 - buffer_max[j]); + if (heigh[j] < 0) + heigh[j] = 0; + if (heigh[j] >= (HEIGHT * 2)) + heigh[j] = (HEIGHT * 2) - 1; + /* low is the current value */ + low[j] = (double)(HEIGHT * 2 - 1) * (1.0 - v); + if (low[j] < 0) + low[j] = 0; + if (low[j] >= (HEIGHT * 2)) + low[j] = (HEIGHT * 2) - 1; } /* plot scaled buffer */ memset(&screen, ' ', sizeof(screen)); memset(&screen_color, 7, sizeof(screen_color)); /* all white */ sprintf(screen[0], "(spectrum log %.0f dB", db); *strchr(screen[0], '\0') = ')'; - for (j = 0; j < width; j++) { + o = (width - fft_size) / 2; /* offset from left border */ + for (j = 0; j < fft_size; j++) { s = e = low[j]; if (j > 0 && low[j - 1] > e) e = low[j - 1] - 1; - if (j < width - 1 && low[j + 1] > e) + if (j < fft_size - 1 && low[j + 1] > e) e = low[j + 1] - 1; if (s == e) { if ((s & 1) == 0) - screen[s >> 1][j] = '\''; + screen[s >> 1][j + o] = '\''; else - screen[s >> 1][j] = '.'; - screen_color[s >> 1][j] = 3; + screen[s >> 1][j + o] = '.'; + screen_color[s >> 1][j + o] = 13; } else { if ((s & 1) == 0) - screen[s >> 1][j] = ':'; + screen[s >> 1][j + o] = ':'; else - screen[s >> 1][j] = '.'; - screen_color[s >> 1][j] = 3; + screen[s >> 1][j + o] = '.'; + screen_color[s >> 1][j + o] = 13; if ((e & 1) == 0) - screen[e >> 1][j] = '\''; + screen[e >> 1][j + o] = '\''; else - screen[e >> 1][j] = ':'; - screen_color[e >> 1][j] = 3; + screen[e >> 1][j + o] = ':'; + screen_color[e >> 1][j + o] = 13; for (k = (s >> 1) + 1; k < (e >> 1); k++) { - screen[k][j] = ':'; - screen_color[k][j] = 3; + screen[k][j + o] = ':'; + screen_color[k][j + o] = 13; } } s = heigh[j]; e = low[j]; if ((s >> 1) < (e >> 1)) { if ((s & 1) == 0) - screen[s >> 1][j] = ':'; + screen[s >> 1][j + o] = ':'; else - screen[s >> 1][j] = '.'; - screen_color[s >> 1][j] = 4; + screen[s >> 1][j + o] = '.'; + screen_color[s >> 1][j + o] = 4; for (k = (s >> 1) + 1; k < (e >> 1); k++) { - screen[k][j] = ':'; - screen_color[k][j] = 4; + screen[k][j + o] = ':'; + screen_color[k][j + o] = 4; } } } @@ -230,7 +218,7 @@ void display_spectrum(float *samples, int length) for (k = 0; k < width; k++) { if (screen_color[j][k] != color) { color = screen_color[j][k]; - printf("\033[1;3%dm", color); + printf("\033[%d;3%dm", color / 10, color % 10); } putchar(screen[j][k]); } |