不韋 呂
Realtime spectrum analyzer. Using FFT, linear prediction, or cepstrum smoothing. Version using MEMS microphone and CODEC, named "F746_RealtimeSpectrumAnalyzer_MEMS_Mic" is registered. リアルタイム スペクトル解析器．解析の手法：FFT，線形予測法，ケプストラムによる平滑化の３種類．このプログラムの説明は，CQ出版社のインターフェース誌，2016年4月号に掲載．外付けのマイクまたは他の信号源等を A0 に接続する．線形予測法，ケプストラムは，スペクトル解析の対象を音声信号に想定してパラメータを設定している．MEMS マイクと CODEC を使ったバージョンを "F746_RealtimeSpectrumAnalyzer_MEMS_Mic" として登録．
Dependencies: BSP_DISCO_F746NG BUTTON_GROUP LCD_DISCO_F746NG TS_DISCO_F746NG UIT_FFT_Real mbed
Diff: MyClasses/Sampler.hpp
- Revision:
- 1:1656f55c2d5c
- Parent:
- 0:5c237fdcba23
- Child:
- 2:095b360e0f54
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/MyClasses/Sampler.hpp Thu Dec 10 04:56:04 2015 +0000
@@ -0,0 +1,93 @@
+//-----------------------------------------------------------
+// Class for sampling input signal
+//
+// 2015/12/08, Copyright (c) 2015 MIKAMI, Naoki
+//-----------------------------------------------------------
+
+#ifndef F746_SAMPLER_HPP
+#define F746_SAMPLER_HPP
+
+#include "mbed.h"
+
+namespace Mikami
+{
+ class Sampler
+ {
+ public:
+ Sampler(PinName pin, Ticker& timer, int nData)
+ : N_DATA_(nData), aIn_(pin), timer_(timer),
+ buffer_(new int16_t[nData])
+ {
+ SetParams(false);
+ inv_ = false;
+ }
+
+ ~Sampler() { delete[] buffer_; }
+
+ void Execute()
+ {
+ int16_t xn = Read();
+ if (!trigger_)
+ {
+ // Detect rising edge
+ if ((xn > (xnM1_+512)) && (xn > 2048))
+ trigger_ = true;
+ else
+ xnM1_ = xn;
+ return;
+ }
+
+ buffer_[count_] = Read(); // Read from A0
+
+ if (++count_ >= N_DATA_)
+ {
+ SetParams(true); // Permits spectrum analysis
+ timer_.detach(); // Disable timer interrupt
+ }
+ }
+
+ void ClearCount() { count_ = 0; }
+
+ bool Filled() { return filled_; }
+
+ void Restart() { filled_ = false; }
+
+ bool InvertEnable(bool onOff)
+ {
+ inv_ = onOff;
+ return onOff;
+ }
+
+ // Get sampled data
+ int16_t* Get() { return buffer_; }
+
+ private:
+ const int N_DATA_; // number of 1 frame data
+
+ AnalogIn aIn_; // Object of ADC
+ Ticker& timer_; // Reference for object of Ticker
+
+ bool trigger_;
+ bool filled_;
+ bool inv_;
+ int count_;
+ int16_t xnM1_;
+
+ int16_t* buffer_; // for sampled data
+
+ int16_t Read()
+ {
+ return inv_ ? 32767 - aIn_.read_u16()
+ : aIn_.read_u16() - 32767;
+ }
+
+ void SetParams(bool tf)
+ {
+ trigger_ = false;
+ count_ = 0;
+ xnM1_ = 32767;
+ filled_ = tf;
+ }
+ };
+}
+#endif // F746_SAMPLER_HPP