2008-06-10 05:29:18 Audio noise AD1854
Zaahir Khan (INDIA)
Message: 56919
Hello All,
I am using BF561 ezkit, customised board.
Having AD1854 audio chip.
When we are running mp3 song. It sounds OK to us.
But when we are running 1k mp3 sine tone, getting tone & small noise, contineously comming.
AD1854 settings
I2S Justified mode,
L/RCLK -----------> 41Khz
BCLK -----------> 3.125 Mhz
Please help!!!!!
Thanks
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2008-06-10 10:01:39 Re: Audio noise AD1854
Robin Getz (UNITED STATES)
Message: 56929
Zaahir:
how are you testing tone? with tone? it is a good idea to use the tone application with the correct sample frequency. In your case - this was "tone -f 41000 5000" play a 5kHz wave with 41kHz samples.
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2008-06-11 00:59:31 Re: Audio noise AD1854
Zaahir Khan (INDIA)
Message: 56957
Hi Robin,
Thanks for your reply.
I am using mp3play.
I have tried "tone" also as you suggested, still getting the noise.
I have attached the 1k.mp3 tone file.
Thanks
1k.mp3
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2008-06-12 00:09:28 Re: Audio noise AD1854
Zaahir Khan (INDIA)
Message: 57055
Hi Robin,
I have tried for some mp3 tone file using mp3play
100Hz_44100Hz_16bit_30sec.mp3
250Hz_44100Hz_16bit_30sec.mp3
for these 2 tone files or these frequencies that noise not there.
But for
440Hz_44100Hz_16bit_30sec.mp3
this frequency and higher ones noise is there
We have probed the audio chip output.
We found that for 100Hz & 250Hz o/p was sine wave with some small glitchs on signal, but OK.
And for 440Hz a bunch of signal say 4 cycles of some small high amplitude & other 4 cycles some less amplitude,
looks like some modulation. And this pattern getting repeated.
Please suggest!!!!
Thanks