File syn_signal.c¶

FileList > dsp > syn_signal.c

Signal statistics implementation.

#include "../util/syn_assert.h"
#include "../util/syn_qmath.h"
#include "syn_signal.h"
#include <limits.h>
#include <string.h>

Public Functions¶

Type	Name
int32_t	syn_signal_at (const SYN_Signal * sig, size_t index) Get sample at index (0 = oldest, count-1 = newest).
void	syn_signal_clear (SYN_Signal * sig) Clear all samples.
int32_t	syn_signal_crest_factor_q16 (SYN_Signal * sig) Signal Crest Factor in Q16.16: Peak / RMS.
int32_t	syn_signal_delta (const SYN_Signal * sig) Rate of change: latest - previous.
void	syn_signal_init (SYN_Signal * sig, int32_t * buf, size_t capacity) Initialize with a caller-provided sample buffer.
int32_t	syn_signal_latest (const SYN_Signal * sig) Get the most recent sample.
int32_t	syn_signal_max (SYN_Signal * sig) Maximum value in the window.
int32_t	syn_signal_min (SYN_Signal * sig) Minimum value in the window.
int32_t	syn_signal_power_q16 (const SYN_Signal * sig) Mean signal power in Q16.16: Σ(x²) / N.
void	syn_signal_push (SYN_Signal * sig, int32_t sample) Push a new sample.
int32_t	syn_signal_rms_q16 (const SYN_Signal * sig) Root-Mean-Square in Q16.16: sqrt(Σ(x²) / N).
int32_t	syn_signal_std_dev_q16 (const SYN_Signal * sig) Standard deviation in Q16.16: sqrt(variance).
int32_t	syn_signal_variance_q16 (const SYN_Signal * sig) Variance in Q16.16 format.

Public Static Functions¶

Type	Name
void	recompute_minmax (SYN_Signal * sig) Recompute cached min/max values over the signal window.

Macros¶

Type	Name
define	INT32_MAX `2147483647` INT32_MAX fallback for pre-C99 compilers.
define	INT32_MIN `(-2147483647 - 1)` INT32_MIN fallback for pre-C99 compilers.

Public Functions Documentation¶

function syn_signal_at¶

Get sample at index (0 = oldest, count-1 = newest).

int32_t syn_signal_at (
    const SYN_Signal * sig,
    size_t index
)

Parameters:

sig Signal instance.
index Sample index.

Returns:

Sample value.

function syn_signal_clear¶

Clear all samples.

void syn_signal_clear (
    SYN_Signal * sig
)

Parameters:

sig Signal instance.

function syn_signal_crest_factor_q16¶

Signal Crest Factor in Q16.16: Peak / RMS.

int32_t syn_signal_crest_factor_q16 (
    SYN_Signal * sig
)

Measures signal peakiness (e.g. 1.414 for sine wave). Returns 0 if RMS is 0 or window is empty.

Parameters:

sig Signal instance.

Returns:

Crest Factor in Q16.16 format.

function syn_signal_delta¶

Rate of change: latest - previous.

int32_t syn_signal_delta (
    const SYN_Signal * sig
)

Returns 0 if fewer than 2 samples.

Parameters:

sig Signal instance.

Returns:

Delta between last two samples.

function syn_signal_init¶

Initialize with a caller-provided sample buffer.

void syn_signal_init (
    SYN_Signal * sig,
    int32_t * buf,
    size_t capacity
)

Parameters:

sig Signal instance.
buf Sample buffer (caller-owned).
capacity Buffer capacity (number of samples).

function syn_signal_latest¶

Get the most recent sample.

int32_t syn_signal_latest (
    const SYN_Signal * sig
)

Parameters:

sig Signal instance.

Returns:

Latest sample, or 0 if empty.

function syn_signal_max¶

Maximum value in the window.

int32_t syn_signal_max (
    SYN_Signal * sig
)

Parameters:

sig Signal instance.

Returns:

Max, or 0 if empty.

function syn_signal_min¶

Minimum value in the window.

int32_t syn_signal_min (
    SYN_Signal * sig
)

Parameters:

sig Signal instance.

Returns:

Min, or 0 if empty.

function syn_signal_power_q16¶

Mean signal power in Q16.16: Σ(x²) / N.

int32_t syn_signal_power_q16 (
    const SYN_Signal * sig
)

Returns 0 if the window is empty.

Parameters:

sig Signal instance.

Returns:

Mean power in Q16.16 format.

function syn_signal_push¶

Push a new sample.

void syn_signal_push (
    SYN_Signal * sig,
    int32_t sample
)

If the window is full, the oldest sample is evicted.

Parameters:

sig Signal instance.
sample New sample value.

function syn_signal_rms_q16¶

Root-Mean-Square in Q16.16: sqrt(Σ(x²) / N).

int32_t syn_signal_rms_q16 (
    const SYN_Signal * sig
)

Returns 0 if the window is empty.

Parameters:

sig Signal instance.

Returns:

RMS value in Q16.16.

function syn_signal_std_dev_q16¶

Standard deviation in Q16.16: sqrt(variance).

int32_t syn_signal_std_dev_q16 (
    const SYN_Signal * sig
)

Returns 0 if fewer than 2 samples.

Parameters:

sig Signal instance.

Returns:

Standard deviation in Q16.16.

function syn_signal_variance_q16¶

Variance in Q16.16 format.

int32_t syn_signal_variance_q16 (
    const SYN_Signal * sig
)

Population variance: Σ(x - mean)² / N, returned as Q16.16. Returns 0 if fewer than 2 samples.

Parameters:

sig Signal instance.

Returns:

Variance in Q16.16.

Public Static Functions Documentation¶

function recompute_minmax¶

Recompute cached min/max values over the signal window.

static void recompute_minmax (
    SYN_Signal * sig
)

Parameters:

sig Signal instance.

Macro Definition Documentation¶

define INT32_MAX¶

INT32_MAX fallback for pre-C99 compilers.

#define INT32_MAX `2147483647`

define INT32_MIN¶

INT32_MIN fallback for pre-C99 compilers.

#define INT32_MIN `(-2147483647 - 1)`

The documentation for this class was generated from the following file src/syntropic/dsp/syn_signal.c