complex.c

ofdm project for Tms320C6000,完整

# include <stdio.h>
# include <math.h>



/**************complex mirror ***********/


void complex(float *frame, float *fft_frame)
{
	int i;
	int j;
	int k;

	
	// real and imaginary part of first null symbol
	fft_frame[0] = 0;
	fft_frame[1] = 0;
	
	// original frame part
	for(i= 0; i<127*2; i++)
	{
	fft_frame[i+2] = frame[i];
	}

	// null symbol
	fft_frame[i+2] = 0;
	fft_frame[i+3] = 0;

	// mirror part
	for(i= 0; i<127*2; i+=2)
	{
		j = i + 127*2 + 4;
		//start from the last data
		k = 127*2 - 2 - i;
		//real part
		fft_frame[j] = frame[k];
		//- imaginary part for conjugate
		fft_frame[j+1] = -frame[k+1];
	}
	
	

}


void complex2(float *frame, float *fft_frame)
{
	int i,j,k;
	//fft frame already set to zeros.
	int subcaroffset=4;
	// original frame part
	for(i= 0; i<(256-subcaroffset*2); i++)
	{
	fft_frame[i+subcaroffset*2] = frame[i];
	}

	
	// mirror part
	for(i= 0; i<(256-subcaroffset*2); i+=2)
	{
		j = i + 256 +2;
		//start from the last data
		k = (256-subcaroffset*2) - 2 - i;
		//real part
		fft_frame[j] = frame[k];
		//- imaginary part for conjugate
		fft_frame[j+1] = -frame[k+1];
	}
	
	

}

/*
void main(void)
{
	float frame[127*2];
	float fft_frame[FFT_SIZE*2];
	int i;

	// original frame
	// store data as real1 imag1 real2 imag2 real3...
	for(i= 0; i<127*2; i+=2)
	{
		frame[i] = i+1;
		frame[i+1] = i+2;
	}
	
	// initialization of fft_frame
	// frame for fft. store as null frame null conj(flip(frame))
	// 0 x1 x2 x3... x127 0 x127* ...x3* x2* x1*
 	for(i= 0; i<FFT_SIZE*2; i++)
	{
		fft_frame[i] = 0;
	}
	
	// mirror operation
	complex(frame, fft_frame);
	
	for(i= 0; i<127*2; i+=2)
	{
		printf("Input=%f, %f \n",frame[i], frame[i+1]);	
	}
	
	printf("\n");	
	
	for(i= 0; i<FFT_SIZE*2; i+=2)
	{
		printf("Output=%f, %f \n",fft_frame[i], fft_frame[i+1]);	
	}
	
} */