WebSVN – svnkaklik – Diff – /programy/C/ix86/echo/SW/sonar/src/sonar.c


///////////////////////////////////////////////////////////////////////////////////
//                        A small demo of sonar.
// Program allow distance measuring.
// Uses cross-correlation algorithm to find echos
//
// Author: kaklik  (kaklik@mlab.cz)
//
///////////////////////////////////////////////////////////////////////////////////
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sched.h>
#include <errno.h>
#include <getopt.h>
#include <alsa/asoundlib.h>
#include <sys/time.h>
#include <math.h>
#include <fftw3.h>
 
#define SOUND_SPEED	340.0	// sound speed in air in metrs per second
#define MAX_RANGE	10.0	// maximal working radius in meters
 
static char *device = "plughw:0,0";			/* playback device */
static snd_pcm_format_t format = SND_PCM_FORMAT_S16;	/* sample format */
static unsigned int rate = 96000;			/* stream rate */
static unsigned int buffer_time = 2 * (MAX_RANGE / SOUND_SPEED * 1e6);		/* ring buffer length in us */
static unsigned int period_time = MAX_RANGE / SOUND_SPEED * 1e6;		/* period time in us */
static int resample = 1;				/* enable alsa-lib resampling */
 
unsigned int chirp_size;
 
static snd_pcm_sframes_t buffer_size;	// size of buffer at sound card
static snd_pcm_sframes_t period_size;	//samples per frame
static snd_output_t *output = NULL;
 
static int set_hwparams(snd_pcm_t *handle, snd_pcm_hw_params_t *params, unsigned int channels)
{
    unsigned int rrate;
    snd_pcm_uframes_t size;
    int err, dir;
 
    /* choose all parameters */
    err = snd_pcm_hw_params_any(handle, params);
    if (err < 0)
    {
        printf("Broken configuration for playback: no configurations available: %s\n", snd_strerror(err));
        return err;
    }
    /* set hardware resampling */
    err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);
    if (err < 0)
    {
        printf("Resampling setup failed for playback: %s\n", snd_strerror(err));
        return err;
    }
    /* set the interleaved read/write format */
    err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
    if (err < 0)
    {
        printf("Access type not available for playback: %s\n", snd_strerror(err));
        return err;
    }
    /* set the sample format */
    err = snd_pcm_hw_params_set_format(handle, params, format);
    if (err < 0)
    {
        printf("Sample format not available for playback: %s\n", snd_strerror(err));
        return err;
    }
    /* set the count of channels */
    err = snd_pcm_hw_params_set_channels(handle, params, channels);
    if (err < 0)
    {
        printf("Channels count (%i) not available for playbacks: %s\n", channels, snd_strerror(err));
        return err;
    }
    /* set the stream rate */
    rrate = rate;
    err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);
    if (err < 0)
    {
        printf("Rate %iHz not available for playback: %s\n", rate, snd_strerror(err));
        return err;
    }
    if (rrate != rate)
    {
        printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);
        return -EINVAL;
    }
    else printf("Rate set to %i Hz\n", rate, err);
    /* set the buffer time */
    err = snd_pcm_hw_params_set_buffer_time_near(handle, params, &buffer_time, &dir);
    if (err < 0)
    {
        printf("Unable to set buffer time %i for playback: %s\n", buffer_time, snd_strerror(err));
        return err;
    }
    err = snd_pcm_hw_params_get_buffer_size(params, &size);
    if (err < 0)
    {
        printf("Unable to get buffer size for playback: %s\n", snd_strerror(err));
        return err;
    }
    buffer_size = size;
    printf("Bufffer size set to:  %d  Requested buffer time: %ld \n", (int) buffer_size, (long) buffer_time);
 
 
    /// set the period time
    err = snd_pcm_hw_params_set_period_time_near(handle, params, &period_time, &dir);
    if (err < 0)
    {
        printf("Unable to set period time %i for playback: %s\n", period_time, snd_strerror(err));
        return err;
    }
 
    err = snd_pcm_hw_params_get_period_size(params, &size, &dir);
    if (err < 0)
    {
        printf("Unable to get period size for playback: %s\n", snd_strerror(err));
        return err;
    }
    period_size = size;
    printf("Period size set to:  %d Requested period time: %ld \n", (int) period_size, (long) period_time);
 
    /* write the parameters to device */
    err = snd_pcm_hw_params(handle, params);
    if (err < 0)
    {
        printf("Unable to set hw params for playback: %s\n", snd_strerror(err));
        return err;
    }
    return 0;
}
 
static int set_swparams(snd_pcm_t *handle, snd_pcm_sw_params_t *swparams)
{
    int err;
 
    /* get the current swparams */
    err = snd_pcm_sw_params_current(handle, swparams);
    if (err < 0)
    {
        printf("Unable to determine current swparams for playback: %s\n", snd_strerror(err));
        return err;
    }
    // start the transfer when the buffer is almost full: never fou our case
    err = snd_pcm_sw_params_set_start_threshold(handle, swparams, 2 * buffer_size);
    if (err < 0)
    {
        printf("Unable to set start threshold mode for playback: %s\n", snd_strerror(err));
        return err;
    }
 
    err = snd_pcm_sw_params_set_period_event(handle, swparams, 1);
    if (err < 0)
    {
        printf("Unable to set period event: %s\n", snd_strerror(err));
        return err;
    }
 
    /* write the parameters to the playback device */
    err = snd_pcm_sw_params(handle, swparams);
    if (err < 0)
    {
        printf("Unable to set sw params for playback: %s\n", snd_strerror(err));
        return err;
    }
    return 0;
}
 
////// SIGNAL GENERATION STUFF
unsigned int linear_windowed_chirp(short *pole)
{
    unsigned int maxval = (1 << (snd_pcm_format_width(format) - 1)) - 1;
 
    static const float f0 = 5000;		//starting frequency
    static const float fmax = 10000;		//ending frequency
    static const float Tw = 0.0015;
    static float k;
 
    unsigned int n=0;
    double t;
    unsigned int chirp_samples;		// number of samples per period
 
    k=2*(fmax-f0)/Tw;
    chirp_samples = ceil(rate*Tw);
 
    for (n=0;n<=chirp_samples;n++)
    {
        t = (double) n / (double)rate;
        pole[n] = (short) floor( (0.35875 - 0.48829*cos(2*M_PI*t*1/Tw) + 0.14128*cos(2*M_PI*2*t*1/Tw) - 0.01168*cos(2*M_PI*3*t*1/Tw))*maxval*sin(2*M_PI*(t)*(f0+(k/2)*(t))) );
    }
    return (chirp_samples);
}
 
int main(int argc, char *argv[])
{
    snd_pcm_t *playback_handle, *capture_handle;
    int err;
    snd_pcm_hw_params_t *hwparams;
    snd_pcm_sw_params_t *swparams;
 
    long int *correlationl, *correlationr;
    int *L_signal, *R_signal;
    short *chirp, *signal;
    float *chirp_spect, *lecho_spect, *recho_spect;
    unsigned int i,j,m,n;
    unsigned int delayl[10],delayr[10];	//store delay of signifed correlation
    long int l,r;  // store correlation at strict time
    double df;	//frequency resolution 
    unsigned int frequency_bins; // number of output frequency bins 
 
    double *inchirp;
    fftw_complex *outchirp;
    fftw_plan fft_plan_chirp;
 
    FILE *out;
 
    snd_pcm_hw_params_alloca(&hwparams);
    snd_pcm_sw_params_alloca(&swparams);
 
    printf("Simple PC sonar ver. 000000001 starting work.. \n");
 
//open and set playback device
    if ((err = snd_pcm_open(&playback_handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0)
    {
        printf("Playback open error: %s\n", snd_strerror(err));
        return 0;
    }
 
    if ((err = set_hwparams(playback_handle, hwparams, 1)) < 0)
    {
        printf("Setting of hwparams failed: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
    if ((err = set_swparams(playback_handle, swparams)) < 0)
    {
        printf("Setting of swparams failed: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
 
//open and set capture device
    if ((err = snd_pcm_open(&capture_handle, device, SND_PCM_STREAM_CAPTURE, 0)) < 0)
    {
        printf("Playback open error: %s\n", snd_strerror(err));
        return 0;
    }
 
    if ((err = set_hwparams(capture_handle, hwparams, 2)) < 0)
    {
        printf("Setting of hwparams failed: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
    if ((err = set_swparams(capture_handle, swparams)) < 0)
    {
        printf("Setting of swparams failed: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
 
    /*    err = snd_pcm_link( capture_handle, playback_handle); //link capture and playback together
        if (err < 0)
        {
            printf("Device linking error: %s\n", snd_strerror(err));
            exit(EXIT_FAILURE);
        }*/
 
    correlationl = malloc(period_size * sizeof(long int)); //array to store correlation curve
    correlationr = malloc(period_size * sizeof(long int)); //array to store correlation curve
    L_signal = malloc(period_size * sizeof(int));
    R_signal = malloc(period_size * sizeof(int));
    chirp = calloc(2*period_size, sizeof(short));
    signal = malloc(2*period_size * sizeof(short));
 
// generate ping pattern
    chirp_size = linear_windowed_chirp(chirp);
 
    frequency_bins = chirp_size / 2 + 1;
    df = (double) rate / (double) chirp_size;
    chirp_spect = malloc(frequency_bins * sizeof(float));
    lecho_spect = malloc(frequency_bins * sizeof(float));
    recho_spect = malloc(frequency_bins * sizeof(float));
 
    inchirp = fftw_malloc(sizeof(double) * chirp_size); 		// allocate input array for FFT
    outchirp = fftw_malloc(sizeof(fftw_complex) * frequency_bins);
 
    fft_plan_chirp = fftw_plan_dft_r2c_1d(chirp_size, inchirp, outchirp, FFTW_ESTIMATE);
 
    printf("compute chirp spectrum\n");
    for(i=0; i < chirp_size; i++) inchirp[i] = chirp[i];
    fftw_execute(fft_plan_chirp);
    for(i=0; i < frequency_bins; i++) chirp_spect[i] = sqrt( outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1] );
 
// write chirp data to souncard buffer
    err = snd_pcm_writei(playback_handle, chirp, period_size);
    if (err < 0)
    {
        printf("Initial write error: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
 
//start sream
    err = snd_pcm_start(playback_handle);
    if (err < 0)
    {
        printf("Start error: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
 
    err = snd_pcm_start(capture_handle);
    if (err < 0)
    {
        printf("Start error: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
    else printf("Waiting for transmitt all samples\n");
//--------------
 
    while ( snd_pcm_avail_update(capture_handle) < period_size)			// wait for one period of data
    {
        usleep(1000);
        printf(".");
    }
 
    err = snd_pcm_drop(playback_handle);		// stop audio stream
    err = snd_pcm_drain(capture_handle);
    if (err < 0)
    {
        printf("Stop error: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
 
    err = snd_pcm_readi(capture_handle, signal, period_size);		//read period from audio buffer
    if (err < 0)
    {
        printf("Read error: %s\n", snd_strerror(err));
        exit(EXIT_FAILURE);
    }
 
    j=0;
    for (i=0;i < period_size;i++)		// separe inretleaved samples to two arrays
    {
        L_signal[i]=signal[j];
        R_signal[i]=signal[j+1];
        j+=2;
    }
 
    printf("\nData transmitted \ncorrelating\n");
    for (n=0; n < (period_size - chirp_size - 1); n++)
    {
        l=0;
        r=0;
        for ( m = 0; m < chirp_size;m++)
        {
            l += chirp[m]*L_signal[m+n];	// correlate with left channel
            r += chirp[m]*R_signal[m+n];	// correlate with right channel
        }
        correlationl[n]=abs(l);
        correlationr[n]=abs(r);
    }
 
    printf("Searching echos\n");
    r=0;
    l=0;
    for (n=0; n < period_size;n++) 			//najde nejvetsi korelace
    {
        if (l < correlationl[n])
        {
            delayl[1] = n;
            l = correlationl[n];
        }
        if (r < correlationr[n])
        {
            delayr[1] = n;
            r = correlationr[n];
        }
    }
 
    for(i=delayl[1]; i < delayl[1] + chirp_size; i++) inchirp[i-delayl[1]] = L_signal[i];
    fftw_execute(fft_plan_chirp);
    for(i=0; i < frequency_bins; i++) lecho_spect[i] = sqrt(outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1]);
 
    for(i=delayr[1]; i < delayr[1] + chirp_size; i++) inchirp[i-delayr[1]] = R_signal[i];
    fftw_execute(fft_plan_chirp);
    for(i=0; i < frequency_bins; i++) recho_spect[i] = sqrt(outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1]);
 
    printf("Writing output files\n");
    out=fopen("/tmp/sonar.txt","w");
    for (i=0; i <= (period_size - 1); i++)
    {
        fprintf(out,"%2.3f %6d %6d %9ld %9ld\n",SOUND_SPEED * (float) i / rate,L_signal[i],R_signal[i],correlationl[i], correlationr[i]);
    }
    fclose(out);
 
    out=fopen("/tmp/chirp.txt","w");
    for (i=0; i <= (chirp_size - 1); i++)
    {
        fprintf(out,"%6d %6d\n", i, chirp[i]);
    }
    fclose(out);
 
    out=fopen("/tmp/echo.txt","w");
    for(i=0; i < chirp_size; i++) fprintf(out,"%6d %6d %6d\n", i, L_signal[i + delayl[1]], R_signal[i + delayr[1]]);
    fclose(out);
 
    out=fopen("/tmp/spektra.txt","w");
    for (i=0; i < frequency_bins; i++)
    {
        fprintf(out,"%4.3f %4.3f %4.3f %4.3f\n", (i+0.5) * df, chirp_spect[i], lecho_spect[i], recho_spect[i]);
    }
    fclose(out);
 
    printf("Echo zacina na: %d vzorku.\n", delayl[1]);
    printf("Casove na: %f s\n", ((float)delayl[1]/rate));
    printf("vzdalenost: %f m\n", (SOUND_SPEED*(float)delayl[1]/rate));
 
    free(correlationl);
    free(correlationr);
    free(L_signal);
    free(R_signal);
    free(chirp);
    free(signal);
 
    snd_pcm_close(playback_handle);
    snd_pcm_close(capture_handle);
    return 0;
}
 

Rev 565	Rev 623
1	`///////////////////////////////////////////////////////////////////////////////////`	1	`///////////////////////////////////////////////////////////////////////////////////`
2	`// A small demo of sonar.`	2	`// A small demo of sonar.`
3	`// Program allow distance measuring.`	3	`// Program allow distance measuring.`
4	`// Uses cross-correlation algorithm to find echos`	4	`// Uses cross-correlation algorithm to find echos`
5	`//`	5	`//`
6	`// Author: kaklik (kaklik@mlab.cz)`	6	`// Author: kaklik (kaklik@mlab.cz)`
7	`//`	7	`//`
8	`///////////////////////////////////////////////////////////////////////////////////`	8	`///////////////////////////////////////////////////////////////////////////////////`
9		9
10	`#include <stdio.h>`	10	`#include <stdio.h>`
11	`#include <stdlib.h>`	11	`#include <stdlib.h>`
12	`#include <string.h>`	12	`#include <string.h>`
13	`#include <sched.h>`	13	`#include <sched.h>`
14	`#include <errno.h>`	14	`#include <errno.h>`
15	`#include <getopt.h>`	15	`#include <getopt.h>`
16	`#include <alsa/asoundlib.h>`	16	`#include <alsa/asoundlib.h>`
17	`#include <sys/time.h>`	17	`#include <sys/time.h>`
18	`#include <math.h>`	18	`#include <math.h>`
19	`#include <fftw3.h>`	19	`#include <fftw3.h>`
20		20
21	`#define SOUND_SPEED 340.0 // sound speed in air in metrs per second`	21	`#define SOUND_SPEED 340.0 // sound speed in air in metrs per second`
22	`#define MAX_RANGE 10.0 // maximal working radius in meters`	22	`#define MAX_RANGE 10.0 // maximal working radius in meters`
23		23
24	`static char device = "plughw:0,0"; / playback device */`	24	`static char device = "plughw:0,0"; / playback device */`
25	`static snd_pcm_format_t format = SND_PCM_FORMAT_S16; /* sample format */`	25	`static snd_pcm_format_t format = SND_PCM_FORMAT_S16; /* sample format */`
26	`static unsigned int rate = 96000; /* stream rate */`	26	`static unsigned int rate = 96000; /* stream rate */`
27	`static unsigned int buffer_time = 2 * (MAX_RANGE / SOUND_SPEED * 1e6); /* ring buffer length in us */`	27	`static unsigned int buffer_time = 2 * (MAX_RANGE / SOUND_SPEED * 1e6); /* ring buffer length in us */`
28	`static unsigned int period_time = MAX_RANGE / SOUND_SPEED * 1e6; /* period time in us */`	28	`static unsigned int period_time = MAX_RANGE / SOUND_SPEED * 1e6; /* period time in us */`
29	`static int resample = 1; /* enable alsa-lib resampling */`	29	`static int resample = 1; /* enable alsa-lib resampling */`
30		30
31	`unsigned int chirp_size;`	31	`unsigned int chirp_size;`
32		32
33	`static snd_pcm_sframes_t buffer_size; // size of buffer at sound card`	33	`static snd_pcm_sframes_t buffer_size; // size of buffer at sound card`
34	`static snd_pcm_sframes_t period_size; //samples per frame`	34	`static snd_pcm_sframes_t period_size; //samples per frame`
35	`static snd_output_t *output = NULL;`	35	`static snd_output_t *output = NULL;`
36		36
37	`static int set_hwparams(snd_pcm_t handle, snd_pcm_hw_params_t params, unsigned int channels)`	37	`static int set_hwparams(snd_pcm_t handle, snd_pcm_hw_params_t params, unsigned int channels)`
38	`{`	38	`{`
39	`unsigned int rrate;`	39	`unsigned int rrate;`
40	`snd_pcm_uframes_t size;`	40	`snd_pcm_uframes_t size;`
41	`int err, dir;`	41	`int err, dir;`
42		42
43	`/* choose all parameters */`	43	`/* choose all parameters */`
44	`err = snd_pcm_hw_params_any(handle, params);`	44	`err = snd_pcm_hw_params_any(handle, params);`
45	`if (err < 0)`	45	`if (err < 0)`
46	`{`	46	`{`
47	`printf("Broken configuration for playback: no configurations available: %s\n", snd_strerror(err));`	47	`printf("Broken configuration for playback: no configurations available: %s\n", snd_strerror(err));`
48	`return err;`	48	`return err;`
49	`}`	49	`}`
50	`/* set hardware resampling */`	50	`/* set hardware resampling */`
51	`err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);`	51	`err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);`
52	`if (err < 0)`	52	`if (err < 0)`
53	`{`	53	`{`
54	`printf("Resampling setup failed for playback: %s\n", snd_strerror(err));`	54	`printf("Resampling setup failed for playback: %s\n", snd_strerror(err));`
55	`return err;`	55	`return err;`
56	`}`	56	`}`
57	`/* set the interleaved read/write format */`	57	`/* set the interleaved read/write format */`
58	`err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);`	58	`err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);`
59	`if (err < 0)`	59	`if (err < 0)`
60	`{`	60	`{`
61	`printf("Access type not available for playback: %s\n", snd_strerror(err));`	61	`printf("Access type not available for playback: %s\n", snd_strerror(err));`
62	`return err;`	62	`return err;`
63	`}`	63	`}`
64	`/* set the sample format */`	64	`/* set the sample format */`
65	`err = snd_pcm_hw_params_set_format(handle, params, format);`	65	`err = snd_pcm_hw_params_set_format(handle, params, format);`
66	`if (err < 0)`	66	`if (err < 0)`
67	`{`	67	`{`
68	`printf("Sample format not available for playback: %s\n", snd_strerror(err));`	68	`printf("Sample format not available for playback: %s\n", snd_strerror(err));`
69	`return err;`	69	`return err;`
70	`}`	70	`}`
71	`/* set the count of channels */`	71	`/* set the count of channels */`
72	`err = snd_pcm_hw_params_set_channels(handle, params, channels);`	72	`err = snd_pcm_hw_params_set_channels(handle, params, channels);`
73	`if (err < 0)`	73	`if (err < 0)`
74	`{`	74	`{`
75	`printf("Channels count (%i) not available for playbacks: %s\n", channels, snd_strerror(err));`	75	`printf("Channels count (%i) not available for playbacks: %s\n", channels, snd_strerror(err));`
76	`return err;`	76	`return err;`
77	`}`	77	`}`
78	`/* set the stream rate */`	78	`/* set the stream rate */`
79	`rrate = rate;`	79	`rrate = rate;`
80	`err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);`	80	`err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);`
81	`if (err < 0)`	81	`if (err < 0)`
82	`{`	82	`{`
83	`printf("Rate %iHz not available for playback: %s\n", rate, snd_strerror(err));`	83	`printf("Rate %iHz not available for playback: %s\n", rate, snd_strerror(err));`
84	`return err;`	84	`return err;`
85	`}`	85	`}`
86	`if (rrate != rate)`	86	`if (rrate != rate)`
87	`{`	87	`{`
88	`printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);`	88	`printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);`
89	`return -EINVAL;`	89	`return -EINVAL;`
90	`}`	90	`}`
91	`else printf("Rate set to %i Hz\n", rate, err);`	91	`else printf("Rate set to %i Hz\n", rate, err);`
92	`/* set the buffer time */`	92	`/* set the buffer time */`
93	`err = snd_pcm_hw_params_set_buffer_time_near(handle, params, &buffer_time, &dir);`	93	`err = snd_pcm_hw_params_set_buffer_time_near(handle, params, &buffer_time, &dir);`
94	`if (err < 0)`	94	`if (err < 0)`
95	`{`	95	`{`
96	`printf("Unable to set buffer time %i for playback: %s\n", buffer_time, snd_strerror(err));`	96	`printf("Unable to set buffer time %i for playback: %s\n", buffer_time, snd_strerror(err));`
97	`return err;`	97	`return err;`
98	`}`	98	`}`
99	`err = snd_pcm_hw_params_get_buffer_size(params, &size);`	99	`err = snd_pcm_hw_params_get_buffer_size(params, &size);`
100	`if (err < 0)`	100	`if (err < 0)`
101	`{`	101	`{`
102	`printf("Unable to get buffer size for playback: %s\n", snd_strerror(err));`	102	`printf("Unable to get buffer size for playback: %s\n", snd_strerror(err));`
103	`return err;`	103	`return err;`
104	`}`	104	`}`
105	`buffer_size = size;`	105	`buffer_size = size;`
106	`printf("Bufffer size set to: %d Requested buffer time: %ld \n", (int) buffer_size, (long) buffer_time);`	106	`printf("Bufffer size set to: %d Requested buffer time: %ld \n", (int) buffer_size, (long) buffer_time);`
107		107
108		108
109	`/// set the period time`	109	`/// set the period time`
110	`err = snd_pcm_hw_params_set_period_time_near(handle, params, &period_time, &dir);`	110	`err = snd_pcm_hw_params_set_period_time_near(handle, params, &period_time, &dir);`
111	`if (err < 0)`	111	`if (err < 0)`
112	`{`	112	`{`
113	`printf("Unable to set period time %i for playback: %s\n", period_time, snd_strerror(err));`	113	`printf("Unable to set period time %i for playback: %s\n", period_time, snd_strerror(err));`
114	`return err;`	114	`return err;`
115	`}`	115	`}`
116		116
117	`err = snd_pcm_hw_params_get_period_size(params, &size, &dir);`	117	`err = snd_pcm_hw_params_get_period_size(params, &size, &dir);`
118	`if (err < 0)`	118	`if (err < 0)`
119	`{`	119	`{`
120	`printf("Unable to get period size for playback: %s\n", snd_strerror(err));`	120	`printf("Unable to get period size for playback: %s\n", snd_strerror(err));`
121	`return err;`	121	`return err;`
122	`}`	122	`}`
123	`period_size = size;`	123	`period_size = size;`
124	`printf("Period size set to: %d Requested period time: %ld \n", (int) period_size, (long) period_time);`	124	`printf("Period size set to: %d Requested period time: %ld \n", (int) period_size, (long) period_time);`
125		125
126	`/* write the parameters to device */`	126	`/* write the parameters to device */`
127	`err = snd_pcm_hw_params(handle, params);`	127	`err = snd_pcm_hw_params(handle, params);`
128	`if (err < 0)`	128	`if (err < 0)`
129	`{`	129	`{`
130	`printf("Unable to set hw params for playback: %s\n", snd_strerror(err));`	130	`printf("Unable to set hw params for playback: %s\n", snd_strerror(err));`
131	`return err;`	131	`return err;`
132	`}`	132	`}`
133	`return 0;`	133	`return 0;`
134	`}`	134	`}`
135		135
136	`static int set_swparams(snd_pcm_t handle, snd_pcm_sw_params_t swparams)`	136	`static int set_swparams(snd_pcm_t handle, snd_pcm_sw_params_t swparams)`
137	`{`	137	`{`
138	`int err;`	138	`int err;`
139		139
140	`/* get the current swparams */`	140	`/* get the current swparams */`
141	`err = snd_pcm_sw_params_current(handle, swparams);`	141	`err = snd_pcm_sw_params_current(handle, swparams);`
142	`if (err < 0)`	142	`if (err < 0)`
143	`{`	143	`{`
144	`printf("Unable to determine current swparams for playback: %s\n", snd_strerror(err));`	144	`printf("Unable to determine current swparams for playback: %s\n", snd_strerror(err));`
145	`return err;`	145	`return err;`
146	`}`	146	`}`
147	`// start the transfer when the buffer is almost full: never fou our case`	147	`// start the transfer when the buffer is almost full: never fou our case`
148	`err = snd_pcm_sw_params_set_start_threshold(handle, swparams, 2 * buffer_size);`	148	`err = snd_pcm_sw_params_set_start_threshold(handle, swparams, 2 * buffer_size);`
149	`if (err < 0)`	149	`if (err < 0)`
150	`{`	150	`{`
151	`printf("Unable to set start threshold mode for playback: %s\n", snd_strerror(err));`	151	`printf("Unable to set start threshold mode for playback: %s\n", snd_strerror(err));`
152	`return err;`	152	`return err;`
153	`}`	153	`}`
154		154
155	`err = snd_pcm_sw_params_set_period_event(handle, swparams, 1);`	155	`err = snd_pcm_sw_params_set_period_event(handle, swparams, 1);`
156	`if (err < 0)`	156	`if (err < 0)`
157	`{`	157	`{`
158	`printf("Unable to set period event: %s\n", snd_strerror(err));`	158	`printf("Unable to set period event: %s\n", snd_strerror(err));`
159	`return err;`	159	`return err;`
160	`}`	160	`}`
161		161
162	`/* write the parameters to the playback device */`	162	`/* write the parameters to the playback device */`
163	`err = snd_pcm_sw_params(handle, swparams);`	163	`err = snd_pcm_sw_params(handle, swparams);`
164	`if (err < 0)`	164	`if (err < 0)`
165	`{`	165	`{`
166	`printf("Unable to set sw params for playback: %s\n", snd_strerror(err));`	166	`printf("Unable to set sw params for playback: %s\n", snd_strerror(err));`
167	`return err;`	167	`return err;`
168	`}`	168	`}`
169	`return 0;`	169	`return 0;`
170	`}`	170	`}`
171		171
172	`////// SIGNAL GENERATION STUFF`	172	`////// SIGNAL GENERATION STUFF`
173	`unsigned int linear_windowed_chirp(short *pole)`	173	`unsigned int linear_windowed_chirp(short *pole)`
174	`{`	174	`{`
175	`unsigned int maxval = (1 << (snd_pcm_format_width(format) - 1)) - 1;`	175	`unsigned int maxval = (1 << (snd_pcm_format_width(format) - 1)) - 1;`
176		176
177	`static const float f0 = 5000; //starting frequency`	177	`static const float f0 = 5000; //starting frequency`
178	`static const float fmax = 10000; //ending frequency`	178	`static const float fmax = 10000; //ending frequency`
179	`static const float Tw = 0.0015;`	179	`static const float Tw = 0.0015;`
180	`static float k;`	180	`static float k;`
181		181
182	`unsigned int n=0;`	182	`unsigned int n=0;`
183	`double t;`	183	`double t;`
184	`unsigned int chirp_samples; // number of samples per period`	184	`unsigned int chirp_samples; // number of samples per period`
185		185
186	`k=2*(fmax-f0)/Tw;`	186	`k=2*(fmax-f0)/Tw;`
187	`chirp_samples = ceil(rate*Tw);`	187	`chirp_samples = ceil(rate*Tw);`
188		188
189	`for (n=0;n<=chirp_samples;n++)`	189	`for (n=0;n<=chirp_samples;n++)`
190	`{`	190	`{`
191	`t = (double) n / (double)rate;`	191	`t = (double) n / (double)rate;`
192	`pole[n] = (short) floor( (0.35875 - 0.48829cos(2M_PIt1/Tw) + 0.14128cos(2M_PI2t1/Tw) - 0.01168cos(2M_PI3t1/Tw))maxvalsin(2M_PI(t)(f0+(k/2)(t))) );`	192	`pole[n] = (short) floor( (0.35875 - 0.48829cos(2M_PIt1/Tw) + 0.14128cos(2M_PI2t1/Tw) - 0.01168cos(2M_PI3t1/Tw))maxvalsin(2M_PI(t)(f0+(k/2)(t))) );`
193	`}`	193	`}`
194	`return (chirp_samples);`	194	`return (chirp_samples);`
195	`}`	195	`}`
196		196
197	`int main(int argc, char *argv[])`	197	`int main(int argc, char *argv[])`
198	`{`	198	`{`
199	`snd_pcm_t playback_handle, capture_handle;`	199	`snd_pcm_t playback_handle, capture_handle;`
200	`int err;`	200	`int err;`
201	`snd_pcm_hw_params_t *hwparams;`	201	`snd_pcm_hw_params_t *hwparams;`
202	`snd_pcm_sw_params_t *swparams;`	202	`snd_pcm_sw_params_t *swparams;`
203		203
204	`long int correlationl, correlationr;`	204	`long int correlationl, correlationr;`
205	`int L_signal, R_signal;`	205	`int L_signal, R_signal;`
206	`short chirp, signal;`	206	`short chirp, signal;`
207	`float chirp_spect, echo_spect;`	207	`float chirp_spect, lecho_spect, *recho_spect;`
208	`unsigned int i,j,m,n;`	208	`unsigned int i,j,m,n;`
209	`unsigned int delayl[10],delayr[10]; //store delay of signifed correlation`	209	`unsigned int delayl[10],delayr[10]; //store delay of signifed correlation`
210	`long int l,r; // store correlation at strict time`	210	`long int l,r; // store correlation at strict time`
211	`double df; //frequency resolution`	211	`double df; //frequency resolution`
212	`unsigned int frequency_bins; // number of output frequency bins`	212	`unsigned int frequency_bins; // number of output frequency bins`
213		213
214	`double *inchirp;`	214	`double *inchirp;`
215	`fftw_complex *outchirp;`	215	`fftw_complex *outchirp;`
216	`fftw_plan fft_plan_chirp;`	216	`fftw_plan fft_plan_chirp;`
217		217
218	`FILE *out;`	218	`FILE *out;`
219		219
220	`snd_pcm_hw_params_alloca(&hwparams);`	220	`snd_pcm_hw_params_alloca(&hwparams);`
221	`snd_pcm_sw_params_alloca(&swparams);`	221	`snd_pcm_sw_params_alloca(&swparams);`
222		222
223	`printf("Simple PC sonar ver. 000000001 starting work.. \n");`	223	`printf("Simple PC sonar ver. 000000001 starting work.. \n");`
224		224
225	`//open and set playback device`	225	`//open and set playback device`
226	`if ((err = snd_pcm_open(&playback_handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0)`	226	`if ((err = snd_pcm_open(&playback_handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0)`
227	`{`	227	`{`
228	`printf("Playback open error: %s\n", snd_strerror(err));`	228	`printf("Playback open error: %s\n", snd_strerror(err));`
229	`return 0;`	229	`return 0;`
230	`}`	230	`}`
231		231
232	`if ((err = set_hwparams(playback_handle, hwparams, 1)) < 0)`	232	`if ((err = set_hwparams(playback_handle, hwparams, 1)) < 0)`
233	`{`	233	`{`
234	`printf("Setting of hwparams failed: %s\n", snd_strerror(err));`	234	`printf("Setting of hwparams failed: %s\n", snd_strerror(err));`
235	`exit(EXIT_FAILURE);`	235	`exit(EXIT_FAILURE);`
236	`}`	236	`}`
237	`if ((err = set_swparams(playback_handle, swparams)) < 0)`	237	`if ((err = set_swparams(playback_handle, swparams)) < 0)`
238	`{`	238	`{`
239	`printf("Setting of swparams failed: %s\n", snd_strerror(err));`	239	`printf("Setting of swparams failed: %s\n", snd_strerror(err));`
240	`exit(EXIT_FAILURE);`	240	`exit(EXIT_FAILURE);`
241	`}`	241	`}`
242		242
243	`//open and set capture device`	243	`//open and set capture device`
244	`if ((err = snd_pcm_open(&capture_handle, device, SND_PCM_STREAM_CAPTURE, 0)) < 0)`	244	`if ((err = snd_pcm_open(&capture_handle, device, SND_PCM_STREAM_CAPTURE, 0)) < 0)`
245	`{`	245	`{`
246	`printf("Playback open error: %s\n", snd_strerror(err));`	246	`printf("Playback open error: %s\n", snd_strerror(err));`
247	`return 0;`	247	`return 0;`
248	`}`	248	`}`
249		249
250	`if ((err = set_hwparams(capture_handle, hwparams, 2)) < 0)`	250	`if ((err = set_hwparams(capture_handle, hwparams, 2)) < 0)`
251	`{`	251	`{`
252	`printf("Setting of hwparams failed: %s\n", snd_strerror(err));`	252	`printf("Setting of hwparams failed: %s\n", snd_strerror(err));`
253	`exit(EXIT_FAILURE);`	253	`exit(EXIT_FAILURE);`
254	`}`	254	`}`
255	`if ((err = set_swparams(capture_handle, swparams)) < 0)`	255	`if ((err = set_swparams(capture_handle, swparams)) < 0)`
256	`{`	256	`{`
257	`printf("Setting of swparams failed: %s\n", snd_strerror(err));`	257	`printf("Setting of swparams failed: %s\n", snd_strerror(err));`
258	`exit(EXIT_FAILURE);`	258	`exit(EXIT_FAILURE);`
259	`}`	259	`}`
260		260
261	`/* err = snd_pcm_link( capture_handle, playback_handle); //link capture and playback together`	261	`/* err = snd_pcm_link( capture_handle, playback_handle); //link capture and playback together`
262	`if (err < 0)`	262	`if (err < 0)`
263	`{`	263	`{`
264	`printf("Device linking error: %s\n", snd_strerror(err));`	264	`printf("Device linking error: %s\n", snd_strerror(err));`
265	`exit(EXIT_FAILURE);`	265	`exit(EXIT_FAILURE);`
266	`}*/`	266	`}*/`
267		267
268	`correlationl = malloc(period_size * sizeof(long int)); //array to store correlation curve`	268	`correlationl = malloc(period_size * sizeof(long int)); //array to store correlation curve`
269	`correlationr = malloc(period_size * sizeof(long int)); //array to store correlation curve`	269	`correlationr = malloc(period_size * sizeof(long int)); //array to store correlation curve`
270	`L_signal = malloc(period_size * sizeof(int));`	270	`L_signal = malloc(period_size * sizeof(int));`
271	`R_signal = malloc(period_size * sizeof(int));`	271	`R_signal = malloc(period_size * sizeof(int));`
272	`chirp = calloc(2*period_size, sizeof(short));`	272	`chirp = calloc(2*period_size, sizeof(short));`
273	`signal = malloc(2period_size sizeof(short));`	273	`signal = malloc(2period_size sizeof(short));`
274		274
275	`// generate ping pattern`	275	`// generate ping pattern`
276	`chirp_size = linear_windowed_chirp(chirp);`	276	`chirp_size = linear_windowed_chirp(chirp);`
277		277
278	`frequency_bins = chirp_size / 2 + 1;`	278	`frequency_bins = chirp_size / 2 + 1;`
279	`df = (double) rate / (double) chirp_size;`	279	`df = (double) rate / (double) chirp_size;`
280	`chirp_spect = malloc(frequency_bins * sizeof(float));`	280	`chirp_spect = malloc(frequency_bins * sizeof(float));`
-		281	`lecho_spect = malloc(frequency_bins * sizeof(float));`
281	`echo_spect = malloc(frequency_bins * sizeof(float));`	282	`recho_spect = malloc(frequency_bins * sizeof(float));`
282		283
283	`inchirp = fftw_malloc(sizeof(double) * chirp_size); // allocate input array for FFT`	284	`inchirp = fftw_malloc(sizeof(double) * chirp_size); // allocate input array for FFT`
284	`outchirp = fftw_malloc(sizeof(fftw_complex) * frequency_bins);`	285	`outchirp = fftw_malloc(sizeof(fftw_complex) * frequency_bins);`
285		286
286	`fft_plan_chirp = fftw_plan_dft_r2c_1d(chirp_size, inchirp, outchirp, FFTW_ESTIMATE);`	287	`fft_plan_chirp = fftw_plan_dft_r2c_1d(chirp_size, inchirp, outchirp, FFTW_ESTIMATE);`
287		288
288	`printf("compute chirp spectrum\n");`	289	`printf("compute chirp spectrum\n");`
289	`for(i=0; i < chirp_size; i++) inchirp[i] = chirp[i];`	290	`for(i=0; i < chirp_size; i++) inchirp[i] = chirp[i];`
290	`fftw_execute(fft_plan_chirp);`	291	`fftw_execute(fft_plan_chirp);`
291	`for(i=0; i < frequency_bins; i++) chirp_spect[i] = sqrt( outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1] );`	292	`for(i=0; i < frequency_bins; i++) chirp_spect[i] = sqrt( outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1] );`
292		293
293	`// write chirp data to souncard buffer`	294	`// write chirp data to souncard buffer`
294	`err = snd_pcm_writei(playback_handle, chirp, period_size);`	295	`err = snd_pcm_writei(playback_handle, chirp, period_size);`
295	`if (err < 0)`	296	`if (err < 0)`
296	`{`	297	`{`
297	`printf("Initial write error: %s\n", snd_strerror(err));`	298	`printf("Initial write error: %s\n", snd_strerror(err));`
298	`exit(EXIT_FAILURE);`	299	`exit(EXIT_FAILURE);`
299	`}`	300	`}`
300		301
301	`//start sream`	302	`//start sream`
302	`err = snd_pcm_start(playback_handle);`	303	`err = snd_pcm_start(playback_handle);`
303	`if (err < 0)`	304	`if (err < 0)`
304	`{`	305	`{`
305	`printf("Start error: %s\n", snd_strerror(err));`	306	`printf("Start error: %s\n", snd_strerror(err));`
306	`exit(EXIT_FAILURE);`	307	`exit(EXIT_FAILURE);`
307	`}`	308	`}`
308		309
309	`err = snd_pcm_start(capture_handle);`	310	`err = snd_pcm_start(capture_handle);`
310	`if (err < 0)`	311	`if (err < 0)`
311	`{`	312	`{`
312	`printf("Start error: %s\n", snd_strerror(err));`	313	`printf("Start error: %s\n", snd_strerror(err));`
313	`exit(EXIT_FAILURE);`	314	`exit(EXIT_FAILURE);`
314	`}`	315	`}`
315	`else printf("Waiting for transmitt all samples\n");`	316	`else printf("Waiting for transmitt all samples\n");`
316	`//--------------`	317	`//--------------`
317		318
318	`while ( snd_pcm_avail_update(capture_handle) < period_size) // wait for one period of data`	319	`while ( snd_pcm_avail_update(capture_handle) < period_size) // wait for one period of data`
319	`{`	320	`{`
320	`usleep(1000);`	321	`usleep(1000);`
321	`printf(".");`	322	`printf(".");`
322	`}`	323	`}`
323		324
324	`err = snd_pcm_drop(playback_handle); // stop audio stream`	325	`err = snd_pcm_drop(playback_handle); // stop audio stream`
325	`err = snd_pcm_drain(capture_handle);`	326	`err = snd_pcm_drain(capture_handle);`
326	`if (err < 0)`	327	`if (err < 0)`
327	`{`	328	`{`
328	`printf("Stop error: %s\n", snd_strerror(err));`	329	`printf("Stop error: %s\n", snd_strerror(err));`
329	`exit(EXIT_FAILURE);`	330	`exit(EXIT_FAILURE);`
330	`}`	331	`}`
331		332
332	`err = snd_pcm_readi(capture_handle, signal, period_size); //read period from audio buffer`	333	`err = snd_pcm_readi(capture_handle, signal, period_size); //read period from audio buffer`
333	`if (err < 0)`	334	`if (err < 0)`
334	`{`	335	`{`
335	`printf("Read error: %s\n", snd_strerror(err));`	336	`printf("Read error: %s\n", snd_strerror(err));`
336	`exit(EXIT_FAILURE);`	337	`exit(EXIT_FAILURE);`
337	`}`	338	`}`
338		339
339	`j=0;`	340	`j=0;`
340	`for (i=0;i < period_size;i++) // separe inretleaved samples to two arrays`	341	`for (i=0;i < period_size;i++) // separe inretleaved samples to two arrays`
341	`{`	342	`{`
342	`L_signal[i]=signal[j];`	343	`L_signal[i]=signal[j];`
343	`R_signal[i]=signal[j+1];`	344	`R_signal[i]=signal[j+1];`
344	`j+=2;`	345	`j+=2;`
345	`}`	346	`}`
346		347
347	`printf("\nData transmitted \ncorrelating\n");`	348	`printf("\nData transmitted \ncorrelating\n");`
348	`for (n=0; n < (period_size - chirp_size - 1); n++)`	349	`for (n=0; n < (period_size - chirp_size - 1); n++)`
349	`{`	350	`{`
350	`l=0;`	351	`l=0;`
351	`r=0;`	352	`r=0;`
352	`for ( m = 0; m < chirp_size;m++)`	353	`for ( m = 0; m < chirp_size;m++)`
353	`{`	354	`{`
354	`l += chirp[m]*L_signal[m+n]; // correlate with left channel`	355	`l += chirp[m]*L_signal[m+n]; // correlate with left channel`
355	`r += chirp[m]*R_signal[m+n]; // correlate with right channel`	356	`r += chirp[m]*R_signal[m+n]; // correlate with right channel`
356	`}`	357	`}`
357	`correlationl[n]=abs(l);`	358	`correlationl[n]=abs(l);`
358	`correlationr[n]=abs(r);`	359	`correlationr[n]=abs(r);`
359	`}`	360	`}`
360		361
361	`printf("Searching echos\n");`	362	`printf("Searching echos\n");`
362	`r=0;`	363	`r=0;`
363	`l=0;`	364	`l=0;`
364	`for (n=0; n < period_size;n++) //najde nejvetsi korelace`	365	`for (n=0; n < period_size;n++) //najde nejvetsi korelace`
365	`{`	366	`{`
366	`if (l < correlationl[n])`	367	`if (l < correlationl[n])`
367	`{`	368	`{`
368	`delayl[1] = n;`	369	`delayl[1] = n;`
369	`l = correlationl[n];`	370	`l = correlationl[n];`
370	`}`	371	`}`
371	`if (r < correlationr[n])`	372	`if (r < correlationr[n])`
372	`{`	373	`{`
373	`delayr[1] = n;`	374	`delayr[1] = n;`
374	`r = correlationr[n];`	375	`r = correlationr[n];`
375	`}`	376	`}`
376	`}`	377	`}`
377		378
378	`for(i=delayl[1]; i < delayl[1] + chirp_size; i++) inchirp[i-delayl[1]] = L_signal[i];`	379	`for(i=delayl[1]; i < delayl[1] + chirp_size; i++) inchirp[i-delayl[1]] = L_signal[i];`
379	`fftw_execute(fft_plan_chirp);`	380	`fftw_execute(fft_plan_chirp);`
380	`for(i=0; i < frequency_bins; i++) echo_spect[i] = sqrt(outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1]);`	381	`for(i=0; i < frequency_bins; i++) lecho_spect[i] = sqrt(outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1]);`
-		382
-		383	`for(i=delayr[1]; i < delayr[1] + chirp_size; i++) inchirp[i-delayr[1]] = R_signal[i];`
-		384	`fftw_execute(fft_plan_chirp);`
-		385	`for(i=0; i < frequency_bins; i++) recho_spect[i] = sqrt(outchirp[i][0] * outchirp[i][0] + outchirp[i][1] * outchirp[i][1]);`
381		386
382	`printf("Writing output files\n");`	387	`printf("Writing output files\n");`
383	`out=fopen("/tmp/sonar.txt","w");`	388	`out=fopen("/tmp/sonar.txt","w");`
384	`for (i=0; i <= (period_size - 1); i++)`	389	`for (i=0; i <= (period_size - 1); i++)`
385	`{`	390	`{`
386	`fprintf(out,"%2.3f %6d %6d %9ld %9ld\n",SOUND_SPEED * (float) i / rate,L_signal[i],R_signal[i],correlationl[i], correlationr[i]);`	391	`fprintf(out,"%2.3f %6d %6d %9ld %9ld\n",SOUND_SPEED * (float) i / rate,L_signal[i],R_signal[i],correlationl[i], correlationr[i]);`
387	`}`	392	`}`
388	`fclose(out);`	393	`fclose(out);`
389		394
390	`out=fopen("/tmp/chirp.txt","w");`	395	`out=fopen("/tmp/chirp.txt","w");`
391	`for (i=0; i <= (chirp_size - 1); i++)`	396	`for (i=0; i <= (chirp_size - 1); i++)`
392	`{`	397	`{`
393	`fprintf(out,"%6d %6d\n", i, chirp[i]);`	398	`fprintf(out,"%6d %6d\n", i, chirp[i]);`
394	`}`	399	`}`
395	`fclose(out);`	400	`fclose(out);`
396		401
397	`out=fopen("/tmp/echo.txt","w");`	402	`out=fopen("/tmp/echo.txt","w");`
398	`for(i=delayl[1]; i < delayl[1] + chirp_size; i++) fprintf(out,"%6d %6d\n", i-delayl[1], L_signal[i]);`	403	`for(i=0; i < chirp_size; i++) fprintf(out,"%6d %6d %6d\n", i, L_signal[i + delayl[1]], R_signal[i + delayr[1]]);`
399	`fclose(out);`	404	`fclose(out);`
400		405
401	`out=fopen("/tmp/spektra.txt","w");`	406	`out=fopen("/tmp/spektra.txt","w");`
402	`for (i=0; i < frequency_bins; i++)`	407	`for (i=0; i < frequency_bins; i++)`
403	`{`	408	`{`
404	`fprintf(out,"%4.3f %4.3f %4.3f\n", (i+0.5) * df, chirp_spect[i], echo_spect[i]);`	409	`fprintf(out,"%4.3f %4.3f %4.3f %4.3f\n", (i+0.5) * df, chirp_spect[i], lecho_spect[i], recho_spect[i]);`
405	`}`	410	`}`
406	`fclose(out);`	411	`fclose(out);`
407		412
408	`printf("Echo zacina na: %d vzorku.\n", delayl[1]);`	413	`printf("Echo zacina na: %d vzorku.\n", delayl[1]);`
409	`printf("Casove na: %f s\n", ((float)delayl[1]/rate));`	414	`printf("Casove na: %f s\n", ((float)delayl[1]/rate));`
410	`printf("vzdalenost: %f m\n", (SOUND_SPEED*(float)delayl[1]/rate));`	415	`printf("vzdalenost: %f m\n", (SOUND_SPEED*(float)delayl[1]/rate));`
411		416
412	`free(correlationl);`	417	`free(correlationl);`
413	`free(correlationr);`	418	`free(correlationr);`
414	`free(L_signal);`	419	`free(L_signal);`
415	`free(R_signal);`	420	`free(R_signal);`
416	`free(chirp);`	421	`free(chirp);`
417	`free(signal);`	422	`free(signal);`
418		423
419	`snd_pcm_close(playback_handle);`	424	`snd_pcm_close(playback_handle);`
420	`snd_pcm_close(capture_handle);`	425	`snd_pcm_close(capture_handle);`
421	`return 0;`	426	`return 0;`
422	`}`	427	`}`
423		428

Subversion Repositories svnkaklik

(root)/programy/C/ix86/echo/SW/sonar/src/sonar.c – Rev 565 → 623