diff options
author | Andreas Eversberg <jolly@eversberg.eu> | 2017-02-05 08:54:56 +0100 |
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committer | Andreas Eversberg <jolly@eversberg.eu> | 2017-02-18 21:02:49 +0100 |
commit | 6a3cfd608e7a3c5d7f0087be43c5197762bae298 (patch) | |
tree | 73f6da0eaa5e8c81f3be77a1ab45f377882427c7 /src/common/display_spectrum.c | |
parent | 3fb2ade35270c8116c094c8ebca0a640a51a14ac (diff) |
Add ascii-art spectrum analyzer for SDR support
Diffstat (limited to 'src/common/display_spectrum.c')
-rw-r--r-- | src/common/display_spectrum.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/src/common/display_spectrum.c b/src/common/display_spectrum.c new file mode 100644 index 0000000..fcdd706 --- /dev/null +++ b/src/common/display_spectrum.c @@ -0,0 +1,247 @@ +/* display spectrum of IQ data + * + * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu> + * All Rights Reserved + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <stdio.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <math.h> +#include "sample.h" +#include "sender.h" +#include "fft.h" + +#define HEIGHT 20 + +static double buffer_max[MAX_DISPLAY_SPECTRUM]; +static char screen[HEIGHT][MAX_DISPLAY_WIDTH]; +static uint8_t screen_color[HEIGHT][MAX_DISPLAY_WIDTH]; +static int spectrum_on = 0; +static double db = 100; + +static dispspectrum_t disp; + +void display_spectrum_init(int samplerate) +{ + memset(&disp, 0, sizeof(disp)); + disp.interval_max = (double)samplerate * DISPLAY_INTERVAL + 0.5; + /* should not happen due to low interval */ + if (disp.interval_max < MAX_DISPLAY_SPECTRUM - 1) + disp.interval_max = MAX_DISPLAY_SPECTRUM - 1; + memset(buffer_max, 0, sizeof(buffer_max)); +} + +void display_spectrum_on(int on) +{ + int j; + int w, h; + + get_win_size(&w, &h); + + if (spectrum_on) { + memset(&screen, ' ', sizeof(screen)); + printf("\0337\033[H"); + for (j = 0; j < HEIGHT; j++) { + screen[j][w] = '\0'; + puts(screen[j]); + } + printf("\0338"); fflush(stdout); + } + + if (on < 0) { + if (++spectrum_on == 2) + spectrum_on = 0; + } else + spectrum_on = on; +} + +void display_spectrum_limit_scroll(int on) +{ + int w, h; + + if (!spectrum_on) + return; + + get_win_size(&w, &h); + + printf("\0337"); + printf("\033[%d;%dr", (on) ? HEIGHT + 1 : 1, h); + printf("\0338"); +} + +/* + * plot spectrum data: + * + */ +void display_spectrum(float *samples, int length) +{ + int width, h; + 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 s, e; + + if (!spectrum_on) + return; + + get_win_size(&width, &h); + if (width > MAX_DISPLAY_SPECTRUM) + width = MAX_DISPLAY_SPECTRUM; + + int heigh[width], low[width]; + + pos = disp.interval_pos; + max = disp.interval_max; + buffer_I = disp.buffer_I; + buffer_Q = disp.buffer_Q; + + for (i = 0; i < length; i++) { + if (pos >= MAX_DISPLAY_SPECTRUM) { + if (++pos == max) + pos = 0; + continue; + } + 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; + k = 0; + for (j = 0; j < MAX_DISPLAY_SPECTRUM; 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]; + 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(); + } + /* 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++) { + s = e = low[j]; + if (j > 0 && low[j - 1] > e) + e = low[j - 1] - 1; + if (j < width - 1 && low[j + 1] > e) + e = low[j + 1] - 1; + if (s == e) { + if ((s & 1) == 0) + screen[s >> 1][j] = '\''; + else + screen[s >> 1][j] = '.'; + screen_color[s >> 1][j] = 3; + } else { + if ((s & 1) == 0) + screen[s >> 1][j] = ':'; + else + screen[s >> 1][j] = '.'; + screen_color[s >> 1][j] = 3; + if ((e & 1) == 0) + screen[e >> 1][j] = '\''; + else + screen[e >> 1][j] = ':'; + screen_color[e >> 1][j] = 3; + for (k = (s >> 1) + 1; k < (e >> 1); k++) { + screen[k][j] = ':'; + screen_color[k][j] = 3; + } + } + s = heigh[j]; + e = low[j]; + if ((s >> 1) < (e >> 1)) { + if ((s & 1) == 0) + screen[s >> 1][j] = ':'; + else + screen[s >> 1][j] = '.'; + screen_color[s >> 1][j] = 4; + for (k = (s >> 1) + 1; k < (e >> 1); k++) { + screen[k][j] = ':'; + screen_color[k][j] = 4; + } + } + } + printf("\0337\033[H"); + for (j = 0; j < HEIGHT; j++) { + for (k = 0; k < width; k++) { + if (screen_color[j][k] != color) { + color = screen_color[j][k]; + printf("\033[1;3%dm", color); + } + putchar(screen[j][k]); + } + printf("\n"); + } + /* reset color and position */ + printf("\033[0;39m\0338"); fflush(stdout); + } + } + + disp.interval_pos = pos; +} + + |