• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 30 subscribers
  • Views 513 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

AIC3262 Digital Microphone offset

Fredrik Bonde
Prodigy 80 points

Hi,

Is it possible to cancel a "DC offset" from a digital microphone with the AIC3262? Can you adjust the PDM reference pulse width to make the offset low or is there any other solution without doing a HPF filter in the mini-DSP?

Best regards
Fredrik Bonde

 

  • 0
    TI__Guru 62076 points

    Yes, you can cancel the DC offset from a digital microhphone with a biquad filter, either using a pre-defined processing block that supports biquad filters or with a custom miniDSP program.

    I suggest choosing a processing block (not a custom miniDSP program) and then programming the first biquad coefficients with a HP-filter that cuts off the DC. You can calculate the coefficients with TIBQ http://www.ti.com/tool/COEFFICIENT-CALC

    Make sure you choose 24-bit coefficients, create the filter as per your requirements in TIBQ, write down the coefficients (click the Coeff button to open the window showing the coefficient) and program the hex values to the ADC coefficient space for the BQ (for example Coeff #0 starts at B40P1R8).

  • 0 in reply to Dominik Hartl11
    Prodigy 80 points

    Thank you! Now we can work on.

    Fredrik