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/SpectrumDisplay.cpp
- Revision:
- 0:5c237fdcba23
- Child:
- 2:095b360e0f54
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/MyClasses/SpectrumDisplay.cpp Wed Dec 09 05:05:00 2015 +0000
@@ -0,0 +1,93 @@
+//-------------------------------------------------------
+// Class for display spectrum
+//
+// 2015/12/07, Copyright (c) 2015 MIKAMI, Naoki
+//-------------------------------------------------------
+
+#include "SpectrumDisplay.hpp"
+
+namespace Mikami
+{
+ SpectrumDisplay::SpectrumDisplay(
+ LCD_DISCO_F746NG &lcd,
+ int nFft, int x0, int y0,
+ float db1, int bin, float maxDb, int fs,
+ uint32_t axisColor, uint32_t lineColor,
+ uint32_t backColor)
+ : N_FFT_(nFft), X0_(x0), Y0_(y0),
+ DB1_(db1), BIN_(bin), MAX_DB_(maxDb),
+ FS_(fs), AXIS_COLOR_(axisColor),
+ LINE_COLOR_(lineColor), BACK_COLOR_(backColor),
+ lcd_(lcd)
+ {
+ AxisX();
+ AxisY();
+ }
+
+ void SpectrumDisplay::Draw(float db[])
+ {
+ const float OFFSET = -60.0f;
+ lcd_.SetTextColor(BACK_COLOR_);
+ lcd_.FillRect(X0_+1, Y0_-(int)(MAX_DB_*DB1_),
+ N_FFT_*BIN_/2, MAX_DB_*DB1_);
+
+ float h = ((db[1] + OFFSET) > 0)? db[1] + OFFSET : 0;
+ int y1 = Y0_ - (int)(h*DB1_);
+ for (int n=1; n<N_FFT_/2; n++)
+ {
+ float h2 = ((db[n+1] + OFFSET) > 0)? db[n+1] + OFFSET : 0;
+ if (h2 > MAX_DB_) h2 = MAX_DB_;
+ int y2 = Y0_ - (int)(h2*DB1_);
+ lcd_.SetTextColor(LINE_COLOR_);
+ lcd_.DrawLine(X0_+n, y1, X0_+n+1, y2);
+ y1 = y2;
+ }
+ lcd_.SetTextColor(AXIS_COLOR_);
+ lcd_.DrawLine(X0_, Y0_, X0_+BIN_*N_FFT_/2, Y0_);
+ }
+
+ // Clear Spectrum
+ void SpectrumDisplay::Clear()
+ {
+ lcd_.SetTextColor(BACK_COLOR_);
+ lcd_.FillRect(X0_+1, Y0_-(int)(MAX_DB_*DB1_),
+ N_FFT_*BIN_/2, MAX_DB_*DB1_);
+ }
+
+ // x-axis
+ void SpectrumDisplay::AxisX()
+ {
+ lcd_.SetFont(&Font12);
+
+ lcd_.SetTextColor(AXIS_COLOR_);
+ lcd_.DrawLine(X0_, Y0_, X0_+BIN_*N_FFT_/2, Y0_);
+ float dx = BIN_*(N_FFT_*1000.0f)/(float)FS_;
+ for (int n=0; n<=(FS_/1000)/2; n++)
+ {
+ int xTick = X0_ + (int)(dx*n + 0.5f);
+ char s[5];
+ sprintf(s, "%d", n);
+ DrawString(xTick-3, Y0_+10, s);
+ lcd_.DrawLine(xTick, Y0_, xTick, Y0_+5);
+ }
+ DrawString(X0_+74, Y0_+24, "Frequency [kHz]");
+ }
+
+ // y-axis
+ void SpectrumDisplay::AxisY()
+ {
+ lcd_.SetFont(&Font12);
+
+ lcd_.SetTextColor(AXIS_COLOR_);
+ lcd_.DrawLine(X0_, Y0_+5, X0_, Y0_-(int)(MAX_DB_*DB1_));
+ for (int n=0; n<=(int)MAX_DB_; n+=20)
+ {
+ int yTick = Y0_-(int)(DB1_*n);
+ char s[5];
+ sprintf(s, "%3d", n);
+ DrawString(X0_-30, yTick-5, s);
+ lcd_.DrawLine(X0_-5, yTick, X0_, yTick);
+ }
+ DrawString(X0_-27, Y0_-(int)(DB1_*MAX_DB_)-18, "[dB]");
+ }
+}