AnsweredAssumed Answered

ADMP421 bias in output signal.

Question asked by ag77 on Feb 27, 2012
Latest reply on Mar 6, 2012 by JeradL

I am working with the ADMP421 MEMS microphone and the ADAU1761. I am also using the ADAU1761 as a codec for an extenal microphone. When the system is configured for the external microphone, there is a zero bias on the output and the high frequency content of the sound is easily picked up. However, when I configure the system for the ADMP421 microphone, I am seeing a very large positive bias on the output, (~15% of the output range). Also, I am not hearing much of the high frequency content of the sound. Is there a setting in SigmaStudio that could be causing this? My company had some problems with the original pad layout suggested for the ADMP421. Could this be a factor in producing the bias I am seeing?

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