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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.cpp
- Revision:
- 8:1f4bc859bc84
- Parent:
- 7:6598a9b70e5a
- Child:
- 12:e5367ab82460
--- a/MyClasses/Sampler.cpp Sun Dec 20 13:38:22 2015 +0000 +++ b/MyClasses/Sampler.cpp Mon Dec 28 08:20:34 2015 +0000 @@ -1,7 +1,7 @@ //----------------------------------------------------------- // Class for sampling input signal // -// 2015/12/20, Copyright (c) 2015 MIKAMI, Naoki +// 2015/12/28, Copyright (c) 2015 MIKAMI, Naoki //----------------------------------------------------------- #include "Sampler.hpp" @@ -10,43 +10,35 @@ { Sampler::Sampler(PinName pin, int fs, int nData) : TS_(1000000/fs), N_DATA_(nData), aIn_(pin), - xn_(new int16_t[nData]), + sn_(new int16_t[nData]), buffer_(new int16_t[nData]) { - Rd[0] = &Sampler::ReadNorm; // inphase - Rd[1] = &Sampler::ReadInv; // out-of-phase - sw_ = 0; - Set(false); - for (int n=0; n<nData; n++) - buffer_[n] = 32767; + for (int n=0; n<nData; n++) sn_[n] = 32767; } Sampler::~Sampler() { - delete[] xn_; + delete[] sn_; delete[] buffer_; } - void Sampler::Start() + // Start sampling + void Sampler::Start(bool onOff) { count_ = 0; filled_ = false; - timer_.attach_us(this, &Sampler::Isr, TS_); - } - - void Sampler::Set(bool tf) - { trigger_ = false; xnM1_ = 32767; - filled_ = tf; + Invert(onOff); + timer_.attach_us(this, &Sampler::Isr, TS_); } // Interrupt service routine for Ticker void Sampler::Isr() { + int16_t xn = (this->*Rd)(); // Read from A0 if (!trigger_) { - int16_t xn = (this->*Rd[sw_])(); // Detect rising edge if ((xn > (xnM1_+512)) && (xn > 2048)) trigger_ = true; @@ -54,14 +46,15 @@ xnM1_ = xn; return; } - - buffer_[count_] = (this->*Rd[sw_])(); // Read from A0 + else + buffer_[count_] = xn; if (++count_ >= N_DATA_) { timer_.detach(); - Set(true); // Permits spectrum analysis - memcpy(xn_, buffer_, N_DATA_*sizeof(int16_t)); + memcpy(sn_, buffer_, N_DATA_*sizeof(int16_t)); + filled_ = true; // Permits spectrum analysis } } } +