ASCII Spectral Periodogram (asgram)

Attention

Work in progress

#include <liquid/liquid.h>

int main() {
    // options
    unsigned int nfft    =   72;    // FFT size (display)
    unsigned int buf_len = 3456;    // input buffer size

    // create spectral periodogram and set scale
    asgramcf q = asgramcf_create(nfft);
    asgramcf_set_scale  (q, -80.0f, 5.0f);
    asgramcf_set_display(q, "...++++###"); // set custom display characters

    // allocated memory arrays
    float complex * buf = (float complex*) malloc(buf_len*sizeof(float complex));

    // ... initialize input ...

    // write block of samples to spectral periodogram object
    asgramcf_write(q, buf, buf_len);

    // print result to screen
    asgramcf_print(q);

    // destroy object and free memory arrays
    asgramcf_destroy(q);
    free(buf);
}

 >                 .......,,,,--+*NN&+--,,,,.......                 < pk 14.1 dB [ 0.00]
 >                  .......,,,,--+&NN*--,,,,........                < pk 14.1 dB [ 0.01]
 >                  .......,,,,--+*&N&+--,,,,.......                < pk 14.1 dB [ 0.02]
 >                 .........,,,,--+*NN&+--,,,........               < pk 14.1 dB [ 0.04]
 >                  .........,,,,,--+&NN*--,,,,......               < pk 14.1 dB [ 0.06]
 >                   ..........,,,,--+*&N&+--,,,.......             < pk 14.1 dB [ 0.09]
 >                    ..........,,,,,--+*&NN*--,,,......            < pk 14.2 dB [ 0.12]
 >                      ...........,,,,---+&NN*--,,,......          < pk 14.2 dB [ 0.15]
 >                       ............,,,,,--+&NN*+-,,,......        < pk 14.2 dB [ 0.18]
 >                         ............,,,,,--+&NN*+-,,,.......     < pk 14.2 dB [ 0.21]
 >                         .............,,,,,--+&NN*+--,,,.....     < pk 14.1 dB [ 0.23]
 >                            ...........,,,,,-+&NN&+--,,,......    < pk 13.9 dB [ 0.23]
 >                             .........,,,,,-+*NN&*+--,,,......    < pk 13.5 dB [ 0.21]
 >                           ..........,,,,-+&NN&*+--,,,.......     < pk 13.2 dB [ 0.18]
 >                          ........,,,,-+&NN&*+--,,,,.......       < pk 12.7 dB [ 0.13]
 >                     ..........,,,-*&NN&*++--,,,........          < pk 12.4 dB [ 0.07]
 >                ...........,,-*&NN&**+--,,,..........             < pk 12.2 dB [-0.01]
 >             ........,,,+*&N&&*++--,,,,......                     < pk 12.1 dB [-0.09]
 >        . ......,,-+&NN&&*+--,,,,........                         < pk 12.3 dB [-0.17]
 >   ........,,,+*NN&&*+--,,,,........                              < pk 12.5 dB [-0.25]
 > .....,,,-+&NN&*++--,,,,.......                               ... < pk 13.0 dB [-0.32]
 > .,,,,-+&NN&*+--,,,,......  .                            ........ < pk 13.4 dB [-0.37]
 > ,,,-+&NN*+--,,,,......                                ........,, < pk 13.8 dB [-0.40]
 > ,,--*NN&+--,,,,......                                .........,, < pk 14.0 dB [-0.41]
 > ,,--+&NN*+-,,,,.....                                .........,,, < pk 14.2 dB [-0.40]
 > ,,,--+*&N&+--,,,......                             ...........,, < pk 14.1 dB [-0.37]
 > .,,,,,--+*NN&+-,,,......                             ........... < pk 14.0 dB [-0.32]
 > .....,,,,--+*&NN*--,,......                             ........ < pk 13.8 dB [-0.27]
 > ........,,,,,--+*&NN*-,,,.......                             ... < pk 13.7 dB [-0.21]
 >    .........,,,,---+*&NN+-,,,.......                             < pk 13.7 dB [-0.15]
 >     ...........,,,,,--+*&NN&+-,,,......                          < pk 13.7 dB [-0.09]
 >           .........,,,,--+*&NN&+-,,,.......                      < pk 13.7 dB [-0.04]
 >               ........,,,,--+*&N&+--,,,........                  < pk 13.9 dB [-0.01]
 >                .........,,,,--+*NN&+-,,,,.......                 < pk 14.0 dB [ 0.02]
 >                   .......,,,,--+*NN&+-,,,,,..........            < pk 14.1 dB [ 0.03]
 >                    .......,,,--+*&N&+--,,,,,........             < pk 14.1 dB [ 0.04]
 >                   ........,,,,--*&N&+--,,,,..........            < pk 14.1 dB [ 0.04]
 >                     ......,,,,-+*NN&+--,,,,..........            < pk 14.2 dB [ 0.04]
 >                    .......,,,--+*NN&+--,,,,.......               < pk 14.1 dB [ 0.03]
 >                   ........,,,--+*NN&+--,,,,.........             < pk 14.1 dB [ 0.03]

Interface

Listed below is the full interface to the asgram family of objects.

create()

Create asgram object with size _nfft

asgramcf = asgramcf_create(unsigned int _nfft);

  • unsigned int _nfft: size of FFT taken for each transform (character width)

  • returns new asgramcf object

asgramf = asgramf_create(unsigned int _nfft);

  • unsigned int _nfft: size of FFT taken for each transform (character width)

  • returns new asgramf object

copy()

Copy object including all internal objects and state

asgramcf = asgramcf_copy(asgramcf _q);

  • asgramcf _q:

  • returns new asgramcf object

asgramf = asgramf_copy(asgramf _q);

  • asgramf _q:

  • returns new asgramf object

destroy()

Destroy asgram object, freeing all internally-allocated memory

int = asgramcf_destroy(asgramcf _q);

  • asgramcf _q:

  • returns standard error code

int = asgramf_destroy(asgramf _q);

  • asgramf _q:

  • returns standard error code

reset()

Reset the internal state of the asgram object

int = asgramcf_reset(asgramcf _q);

  • asgramcf _q:

  • returns standard error code

int = asgramf_reset(asgramf _q);

  • asgramf _q:

  • returns standard error code

set_scale()

Set the scale and offset for spectrogram in terms of dB for display purposes

int = asgramcf_set_scale(asgramcf _q, float _ref, float _div);

  • asgramcf _q: asgram object

  • float _ref: signal reference level

  • float _div: signal division

  • returns standard error code

int = asgramf_set_scale(asgramf _q, float _ref, float _div);

  • asgramf _q: asgram object

  • float _ref: signal reference level

  • float _div: signal division

  • returns standard error code

set_display()

Set the display’s 10 characters for output string starting from the weakest and ending with the strongest

int = asgramcf_set_display(asgramcf _q, const char * _ascii);

  • asgramcf _q: asgram object

  • const char * _ascii: 10-character display, default: “ .,-+*&NM#”

  • returns standard error code

int = asgramf_set_display(asgramf _q, const char * _ascii);

  • asgramf _q: asgram object

  • const char * _ascii: 10-character display, default: “ .,-+*&NM#”

  • returns standard error code

push()

Push a single sample into the asgram object, executing internal transform as necessary.

int = asgramcf_push(asgramcf _q, float complex _x);

  • asgramcf _q: asgram object

  • float complex _x: input sample

  • returns standard error code

int = asgramf_push(asgramf _q, float _x);

  • asgramf _q: asgram object

  • float _x: input sample

  • returns standard error code

write()

Write a block of samples to the asgram object, executing internal transforms as necessary.

int = asgramcf_write(asgramcf _q, float complex * _x, unsigned int _n);

  • asgramcf _q: asgram object

  • float complex * _x: input buffer

  • unsigned int _n: input buffer length

  • returns standard error code

int = asgramf_write(asgramf _q, float * _x, unsigned int _n);

  • asgramf _q: asgram object

  • float * _x: input buffer

  • unsigned int _n: input buffer length

  • returns standard error code

execute()

Compute spectral periodogram output from current buffer contents and return the ascii character string to display along with the peak value and its frequency location

int = asgramcf_execute(asgramcf _q, char * _ascii, float * _peakval, float * _peakfreq);

  • asgramcf _q: asgram object

  • char * _ascii: output ASCII string

  • float * _peakval: peak power spectral density value

  • float * _peakfreq: peak power spectral density frequency

  • returns standard error code

int = asgramf_execute(asgramf _q, char * _ascii, float * _peakval, float * _peakfreq);

  • asgramf _q: asgram object

  • char * _ascii: output ASCII string

  • float * _peakval: peak power spectral density value

  • float * _peakfreq: peak power spectral density frequency

  • returns standard error code

print()

Compute spectral periodogram output from current buffer contents and print standard format to stdout

int = asgramcf_print(asgramcf _q);

  • asgramcf _q:

  • returns standard error code

int = asgramf_print(asgramf _q);

  • asgramf _q:

  • returns standard error code