不韋 呂
Output the audio signal (*.bin) with filtering by IIR filter in the SD card using onboard CODEC. For *.wav file, F746_SD_WavPlayer and F746_SD_GraphicEqualiser are published on mbed. SD カードのオーディオ信号 (*.bin) 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．*.wav 形式のファイル用には，F746_SD_WavPlayer と F746_SD_GraphicEqualiser を mbed で公開している．
Dependencies: BSP_DISCO_F746NG_patch_fixed F746_GUI LCD_DISCO_F746NG SDFileSystem_Warning_Fixed TS_DISCO_F746NG mbed
Diff: MyClasses_Functions/IIR_CascadeFrqResp.hpp
- Revision:
- 3:492cb0f68526
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/MyClasses_Functions/IIR_CascadeFrqResp.hpp Sat Apr 16 13:53:26 2016 +0000
@@ -0,0 +1,48 @@
+//-----------------------------------------------------------
+// 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
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