singenerator.cpp

基于Windows CE的正旋信号发生程序

// SinGenerator.cpp: implementation of the CSinGenerator class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "PSignalGenerate.h"
#include "SinGenerator.h"
#include "math.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

/*  this is a matlab language source code for Oscillator
     
%--------------------------------------------------
%   1/ Test the Discrete Oscillator
%--------------------------------------------------
% recursive resonator filter:
%          y(n) = 2cos(wo).y(n-1) -y(n-2)
%
% initiales conditions    
%         y(-1) = 0 , y(-2) = -Asin(wo)
%
% wo = 2*pi*fo/fs
% fo = Output frequency  must be < fs/2
% fs = sampling frequency
%--------------------------------------------------
clear;
fo = 500;  
fs = 11025;
N = 100; % sequence lenth
wo = 2*pi*fo/fs;

%------------------------
% Set initial conditions
y(1)= -sin(wo);  % for y(-2)
y(2)= 0;         % for y(-1)

%---------------------------
% compute the sequence y(n)
for J = 3:N,
  y(J) = 2*cos(wo)*y(J-1)-y(J-2);
end

  first samples
   -0.2811         0    0.2811    0.5396    0.7545    0.9086    0.9894


*/
//#define SHORT 

CSinGenerator::CSinGenerator()
{
	double pi = 4.0*atan(1.0);
	fo = 300;  
	fs = (double)m_WaveOutSampleRate;
	wo = 2*pi*fo/fs;
	Ampl = 10000;
	m_2cosWo =2*cos(wo);

	SetInitialConditions();
	m_Toggle = 0;
	ComputeSamples(NULL);
	m_Toggle = 1;
	ComputeSamples(NULL);
}

CSinGenerator::~CSinGenerator()
{

}


void CSinGenerator::SetInitialConditions()
{
	OutputBufferR[1][m_NbMaxSamples-2]= (double) (Ampl * -sin(wo)); 
	OutputBufferR[1][m_NbMaxSamples-1]= 0;        
}



void CSinGenerator::ComputeSamples(SHORT *unused)
{
   if (m_Toggle)
   {
		OutputBufferR[1][0] = (double)( m_2cosWo*OutputBufferR[0][m_NbMaxSamples-1]-OutputBufferR[0][m_NbMaxSamples-2]);
		OutputBuffer[1][0] = (SHORT)OutputBufferR[1][0];
		OutputBufferR[1][1] = (double)( m_2cosWo*OutputBufferR[1][0]-OutputBufferR[0][m_NbMaxSamples-1]);
		OutputBuffer[1][1] = (SHORT)OutputBufferR[1][1];
		for (int i = 2; i< m_NbMaxSamples; i++)
		{
			OutputBufferR[1][i] = (double)( m_2cosWo*OutputBufferR[1][i-1]-OutputBufferR[1][i-2]);
			OutputBuffer[1][i] = (SHORT)OutputBufferR[1][i];
		}
   }
	else
	{
		OutputBufferR[0][0] = (double)( m_2cosWo*OutputBufferR[1][m_NbMaxSamples-1]-OutputBufferR[1][m_NbMaxSamples-2]);
		OutputBuffer[0][0] = (SHORT)OutputBufferR[0][0];
		OutputBufferR[0][1] = (double)( m_2cosWo*OutputBufferR[0][0]-OutputBufferR[1][m_NbMaxSamples-1]);
		OutputBuffer[0][1] = (SHORT)OutputBufferR[0][1];

		for (int i = 2; i< m_NbMaxSamples; i++)
		{
			OutputBufferR[0][i] = (double)( m_2cosWo*OutputBufferR[0][i-1]-OutputBufferR[0][i-2]);
			OutputBuffer[0][i] = (SHORT)OutputBufferR[0][i];
		}
	}
}

void CSinGenerator::SetSinParametres(SHORT A, double freq)
{
  Ampl = A; 
  fo= freq;
}

void CSinGenerator::Restart()
{
	double pi = 4.0*atan(1.0);

	CloseOutput();
	wo = 2*pi*fo/fs;
	m_2cosWo =2*cos(wo);

	SetInitialConditions();
	m_Toggle = 0;
	ComputeSamples(NULL);
	m_Toggle = 1;
	ComputeSamples(NULL);
	OpenOutput();

	
}