PCMD3140: PCMD3140 upto 80Khz

MALIK Naveed Akhter

Part Number: PCMD3140

Tool/software:

Is it possible to use the PCMD3140 to capture ultrasound up to 80 kHz from SPH0641LU4H‑1 PDM microphone? If so, how do I configure the Biquad filters in the PurePath Console to extend to 80 kHz? Right now I can’t set the filters above 23 kHz.

4 months ago

0 Lakshmi Narasimhan Badrinarayanan 4 months ago

TI__Expert 8050 points

Hi Malik,

The PCMD3140 supports decimation at sampling rates of 192kHz and 384kHz as described in the datasheet.

The app note highlighted below specifies the max. number of channels that can be operated at these sampling rates.

Thanks and Regards,

Lakshmi Narasimhan

0 MALIK Naveed Akhter 4 months ago in reply to Lakshmi Narasimhan Badrinarayanan

Prodigy 40 points

Thanks for that Lakshmi.
I’m still having some trouble with PurePath Console though. For biquads, I can set the cutoff frequencies to what I want, but the graph only shows up to 23 kHz. Is there any workaround for that?

0 Lakshmi Narasimhan Badrinarayanan 4 months ago in reply to MALIK Naveed Akhter

TI__Expert 8050 points

Hi Malik,

That could be because PurePath Console is considering a 48kHz sampling rate when computing the frequency response. This would scale with actual sampling rate.

Eg. If a 1kHz filter is programmed for a 48kHz sampling rate, at 96kHz, for the same coefficients the cutoff frequency would be 2kHz.

Thanks and Regards,

Lakshmi Narasimhan

0 Lakshmi Narasimhan Badrinarayanan 4 months ago in reply to Lakshmi Narasimhan Badrinarayanan

TI__Expert 8050 points

Hi Malik,

Since we are tracking the issue with PurePath Console on your other thread ((1) PUREPATHCONSOLE: Biquads graph wont go above 23khz - Audio forum - Audio - TI E2E support forums), I will go ahead and close this thread.

Thanks and Regards,

Lakshmi Narasimhan