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Altera_Forum's avatar
Altera_Forum
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9 years ago

I get a big noise when I echo the audio data from microphone

I designed a audio system in Qsys. I read the fifo data from the microphone input and write it to the audio write fifo. Although I can hear the microphone echo, it also generate a very big noise. I c...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 years ago

If I choose 16 bits as my audio data bit length, the max value becomes 65535 and min value becomes 0?

I am not sure the C program is running under 50MHz or not.. If it is, i think my synthetic audio signal is: 


// for tri wave
int tri_signal = 0;
while (1){
	for(int n = 0; n<12500; n++){
		tri_signal = tri_signal + 5;
	}
	tri_signal = 0
}
// for sine wave (not smooth)
int sine_signal = 32767;
while (1){
	for(int n = 0; n<3125; n++){
		sine_signal = sine_signal + 10;
	}
	for(int n = 0; n < 6250; n++){
		sine_signal = sine_signal - 10;
	}
	for(int n = 0; n < 3125; n++){
		sine_signal = sine_signal + 10;
	}
}