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ColdFire QADC for voice audio?

We are considering using the 10 bit QADC on the ColdFire MCF5282 for sampling up to 5 channels of voice audio with 8Khz to 16Khz sampling. I am curious as to whether anyone has experience with this ADC for voice audio applications and in particular whether they experienced excessive digital noise, distortion, or other unforseen problems. The alternative is to use external Codecs to digitize the audio be we are willing to trade a certain amount of audio quality for lower power and chip count.

Thanks, Gordon Higbie Software Engineer Universal Avionics Systems Corporation

Reply to
ghigbie
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Download Texas Inst's FilterPro for an easy way to fiddle with LPF's

HTH

Martin

Reply to
Martin Griffith

I am not particularly familiar with the ADC of the Coldfire, however I have used the built-in 10bit ADCs of the other MCUs for the audio sampling. It is indeed possible to achieve the voice quality similar to that of the phone line. You will need to oversample the signal at least by the factor of two. An analog anti aliasing filter is required in front of the ADC; the 4th order filter is sufficient. It is also necessary to apply the preemphasis; that improves the quality a lot.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

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Reply to
Vladimir Vassilevsky

If you are willing to trade certain amount of audio quality, then you can proceed with this. No problem, it is suitable for that scenario.

Karthik Balaguru

Reply to
karthikbalaguru

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