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AGC settings in Purepath

Diego Pardo
Prodigy 20 points
Other Parts Discussed in Thread: TLV320AIC3254

I have a small question you could easily solve.

 When adding an AGC to the Purepath project these settings are showed (by clicking on the AGC icon):

 

 

They seem to be the AGC settings showed in appn_3254_slaa408a.pdf section 2.3.2.3 (AGC): registers in page 0 for left and right AGC.

But generated purepath .cfg shows a list of coefficients (registers in page 44), and no of those are in page 0.

 

E.G.

by changing  the AGC_DEC_FACTOR value in purepath we can observe coefficient 15 of DAC changing in the .cfg file.

 Are those AGC_xxx settings related to the DAC only? (then non-related to the AGC itself)

  • 0
    TI__Guru* 84915 points

    Hi, Diego,

    Welcome to E2E and thank you for your interest in our products.

    All the algorithms and blocks in PurePath Studio are related with the miniDSP coefficients. So, the AGC blocks in PurePath Studio are not the AGCs of registers 86-101 (page 0).

    The TLV320AIC3254 has two programmable miniDSPs: one in ADC's side and one in DAC's side. If the AGC is configured to be used in miniDSP_A (ADC), it will use the coefficients of ADC. Probably, your AGC block is configured in DAC's side (miniDSP_D) because you're observing a change in coefficient 15 of DAC.

    I hope this helps you. If you still have questions or comments, please let me know.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 20 points

    Thanks Luis F., now it is clear...

    - just one more question:

    I'm cheking dB values are presented as nominal values, e.g:

    AGC_MIN_AUDIO = -60dB => 10^(-60/20) = 0.00998...
    ; and the same for other parameters (it seems all of them are corrected -2^-23).

    >> But how the AGC_INC_FACTOR & AGC_DEC_FACTOR are calculated/represented???