sfddetection.cpp

扩展的直序扩频系统

#include "Common.h"

void SFD(complex CEsequence[PREAMBLE_LENGTH], FILE *fpt_RxSignal)
{
	int i=0, sfdflag=0;
	complex sfdbuffer[PREAMBLE_LENGTH*2] = {0.f, 0.f};
	float value = 0.f;

	fread(sfdbuffer, sizeof(complex), PREAMBLE_LENGTH, fpt_RxSignal);

	for (i=0; i<PREAMBLE_LENGTH; i++)
	{
		value = value + CEsequence[i].real * sfdbuffer[i].real
			+ CEsequence[i].imag * sfdbuffer[i].imag;
	}
	if (value < 0)
	{
		sfdflag = 1;
	}	
			
	while(sfdflag != 1)
	{
		fread(CEsequence, sizeof(complex), PREAMBLE_LENGTH, fpt_RxSignal); 
		
		value = 0.f;

		for (i=0; i<PREAMBLE_LENGTH; i++)
		{
			value = value + CEsequence[i].real * sfdbuffer[i].real
				+ CEsequence[i].imag * sfdbuffer[i].imag;
			sfdbuffer[i] = CEsequence[i];
		}

		if (value < 0)
		{
			sfdflag = 1;
		}
	}
}