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'sweeplf' tells us antenna's resonant frequency

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adam@algroup.co.uk 2009-07-08 02:15:22 +00:00
parent 8172fb35dd
commit 38b65694d6
1 changed files with 24 additions and 1 deletions
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25
armsrc/appmain.c
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@ -241,7 +241,9 @@ static int AvgAdc(int ch)
void SweepLFrange() void SweepLFrange()
{ {
BYTE *dest = (BYTE *)BigBuf; BYTE *dest = (BYTE *)BigBuf;
int i; BYTE dummy[12];
int i, peak= 0, ptr= 0;
double freq;
// clear buffer // clear buffer
memset(BigBuf,0,sizeof(BigBuf)); memset(BigBuf,0,sizeof(BigBuf));
@ -251,7 +253,28 @@ void SweepLFrange()
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, i); FpgaSendCommand(FPGA_CMD_SET_DIVISOR, i);
SpinDelay(20); SpinDelay(20);
dest[i] = (137500 * AvgAdc(ADC_CHAN_LF)) >> 18; dest[i] = (137500 * AvgAdc(ADC_CHAN_LF)) >> 18;
if(dest[i] > peak) {
peak= dest[i];
ptr= i;
}
} }
dummy[11]= '\0';
dummy[10]= 'z';
dummy[9]= 'H';
dummy[8]= 'k';
dummy[7]= ' ';
freq= 12000000/(ptr + 1);
for(i= 6; i > 3 ; --i) {
dummy[i]= '0' + ((int) freq) % 10;
freq /= 10;
}
dummy[3]= '.';
for(i= 2; i >= 0 ; --i) {
dummy[i]= '0' + ((int) freq) % 10;
freq /= 10;
}
DbpString("Antenna resonates at:");
DbpString(dummy);
} }
void MeasureAntennaTuning(void) void MeasureAntennaTuning(void)