dsps_fir_f32_ansi.c File Reference

#include "dsps_fir.h"

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Functions
esp_err_t	dsps_fir_f32_ansi (fir_f32_t *fir, const float *input, float *output, int len)
	32 bit floating point FIR filter

Function Documentation

dsps_fir_f32_ansi()

esp_err_t dsps_fir_f32_ansi	(	fir_f32_t *	fir,
		const float *	input,
		float *	output,
		int	len )

32 bit floating point FIR filter

Function implements FIR filter The extension (_ansi) uses ANSI C and could be compiled and run on any platform. The extension (_ae32) is optimized for ESP32 chip.

Parameters

	fir	pointer to fir filter structure, that must be initialized before
[in]	input	input array
[out]	output	array with the result of FIR filter
[in]	len	length of input and result arrays

Returns

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

Definition at line 17 of file dsps_fir_f32_ansi.c.

{
    for (int i = 0 ; i < len ; i++) {
        float acc = 0;
        int coeff_pos = 0;
        fir->delay[fir->pos] = input[i];
        fir->pos++;
        if (fir->pos >= fir->N) {
            fir->pos = 0;
        }
        for (int n = fir->pos; n < fir->N ; n++) {
            acc += fir->coeffs[coeff_pos++] * fir->delay[n];
        }
        for (int n = 0; n < fir->pos ; n++) {
            acc += fir->coeffs[coeff_pos++] * fir->delay[n];
        }
        output[i] = acc;
    }
    return ESP_OK;
}

References fir_f32_s::coeffs, fir_f32_s::delay, ESP_OK, fir_f32_s::N, N, n, and fir_f32_s::pos.

Referenced by test_fir().

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