dsps_tone_gen.c File Reference

#include "dsps_tone_gen.h"
#include <math.h>

Include dependency graph for dsps_tone_gen.c:

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Functions
esp_err_t	dsps_tone_gen_f32 (float *output, int len, float Ampl, float freq, float phase)
	tone

Function Documentation

dsps_tone_gen_f32()

esp_err_t dsps_tone_gen_f32	(	float *	output,
		int	len,
		float	Ampl,
		float	freq,
		float	phase )

tone

The function generate a tone signal. x[i]=A*sin(2*PI*i + ph/180*PI) The implementation use ANSI C and could be compiled and run on any platform

Parameters

output	output array.
len	length of the input signal
Ampl	amplitude
freq	Naiquist frequency -1..1
phase	phase in degree

Returns

• ESP_OK on success
• One of the error codes from DSP library

Definition at line 18 of file dsps_tone_gen.c.

{
    if (freq >= 1) {
        return ESP_ERR_DSP_INVALID_PARAM;
    }
    if (freq <= -1) {
        return ESP_ERR_DSP_INVALID_PARAM;
    }
    float ph = phase / 180 * M_PI;
    float fr  = 2 * M_PI * freq;
    for (int i = 0 ; i < len ; i++) {
        output[i] = Ampl * sin(ph);
        ph += fr;
        if (ph > 2 * M_PI) {
            ph -= 2 * M_PI;
        }
        if (ph < -2 * M_PI) {
            ph += 2 * M_PI;
        }
    }
    return ESP_OK;
}

References ESP_ERR_DSP_INVALID_PARAM, ESP_OK, and M_PI.