不韋 呂 / Mbed 2 deprecated F746_SD_WavPlayer

Output the audio signal with filtering by IIR filter in the *.wav file on the SD card using onboard CODEC. SD カードの *.wav ファイルのオーディオ信号を遮断周波数可変の IIR フィルタを通して，ボードに搭載されているCODEC で出力する．

Dependencies:   BSP_DISCO_F746NG F746_GUI LCD_DISCO_F746NG SDFileSystem_Warning_Fixed TS_DISCO_F746NG mbed FrequencyResponseDrawer F746_SAI_IO Array_Matrix

MyClasses_Functions/IIR_CascadeFrqResp.hpp

Committer:
MikamiUitOpen
Date:
2016-07-04
Revision:
11:769d986c10fa
Parent:
0:04b43b777fae

File content as of revision 11:769d986c10fa:

//-----------------------------------------------------------
//  Frequency response for IIR filter of cascade form
//
//  2016/04/16, Copyright (c) 2016 MIKAMI, Naoki
//-----------------------------------------------------------

#ifndef IIR_CASCADE_FREQUENCY_RESPONSE_HPP
#define IIR_CASCADE_FREQUENCY_RESPONSE_HPP

#include "FrequancyResponseBase.hpp"
#include "Biquad.hpp"

namespace Mikami
{
    class IIR_CascadeFrqResp : public FrequencyResponse
    {
    public:
        IIR_CascadeFrqResp() {}

        // 次数とフィルタの係数設定
        void SetParams(int order, float g0, Biquad::Coefs ck[])
        {
            order_ = order;
            g0_ = g0;
            ck_ = ck;
        }

        // 周波数応答の絶対値を返す関数, 引数: z^(-1)
        virtual float AbsH_z(Complex u)
        {
            Complex h = g0_;
            for (int k=0; k<order_/2; k++)
            h = h*(1.0f + (ck_[k].b1 + ck_[k].b2*u)*u)
                /((1.0f - (ck_[k].a1 + ck_[k].a2*u)*u));
            return abs(h);       
        }
        
    private:
        int order_;
        float g0_;
        Biquad::Coefs *ck_;

        // disallow copy constructor and assignment operator
        IIR_CascadeFrqResp(const IIR_CascadeFrqResp&);
        IIR_CascadeFrqResp& operator=(const IIR_CascadeFrqResp&);
    };
}
#endif  // IIR_CASCADE_FREQUENCY_RESPONSE_HPP