dsps_tone_gen.c

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// Copyright 2018-2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#include "dsps_tone_gen.h"
#include <math.h>
 
esp_err_t dsps_tone_gen_f32(float *output, int len, float Ampl, float freq, float phase)
{
    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;
}