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PCM5242 44.1KHz EQ ISSUE

Bing Dong
Prodigy 450 points
Other Parts Discussed in Thread: PCM5242

Hi team,

I have a issue about PCM5242 EQ:

Issue: Using 44.1Khz sampling rate ,EQ may not take effect,but 48Khz sampling rate ,it works well.

Testing condition: Using our PCM5242 EVM, PSIA input LRCLK=44.1KHz/48kHz,Bit clock=2.8224MHz,MCLK=11.289MHz,

Configuration in PPC 2 is using Hybridflow1 or 6, There is a EQ at 1Khz -6dB Gain, Q=1.6, xml file  is attached for your reference.

Input digital signal is 0.5FFS, 1Khz

Testing results are listed as below, EQ may note take effect at 44.1Khz sampling rate.MyPCM5242MHF6_HF6_44Khz.xml

 

 

GUI Configure in PPC2

LRCLK input

Output voltage

0dB at 1Khz (no EQ)

44.1K

44.1K

4Vrms

-6dB at 1Khz

44.1K

44.1K

4Vrms

-6dB at 1Khz

44.1K

48k

4Vrms

-6dB at 1Khz

48k

48k

1.992Vrms
  • 0
    TI__Guru 57800 points

    Hi, Bing,

    Thanks for your question, my colleague will take a look to this and will get back to you soon.

    Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Mastermind 27990 points

    Hi Bing,

    Are you changing the sampling rate physically with the clock as well as in the GUI drop down? It will require a reprogramming of the DSP as well to change the coefficients. This means that in the GUI you will have to stop the DSP by hitting the red button in the top right, then change the sampling rate, then start the DSP again. If you want to test if you have the biquad enabled, but for the wrong sampling rate, do a frequency response and see if your desired response is just shifted in frequency.

    Justin