Hello
My customer is evaluating head phone output zipper noise of volume change
at their final set( Pre Production) using TLV320AIC3101.
According to customer, Volume control using P0 R47, P0 R64 has zipper noise, due to
they set HPLout/HPRout Level control=6dB fixed ( zipper noise has amplified ).
So, Customer intend to use HPLout/HPRout on the fly if total volume is greater than 0dB.
That is to say,
when total volume is 0dB, Volume control using P0 R47, P0 R64 is 0dB and HPLout/HPRout Level control=0dB.
When total volume is -6dB, Volume control using P0 R47, P0 R64 is -6dB and HPLout/HPRout Level control=0dB.
When total volume is +3dB, Volume control using P0 R47, P0 R64 is 0 dB and HPLout/HPRout Level control=3dB.
When total volume is +6dB, Volume control using P0 R47, P0 R64 is 0 dB and HPLout/HPRout Level control=6dB.
According to customer, this action ( *CASE-B Corrective action*) had better, and no extra problem found .
Question
In the TLV320AIC3101 data sheet page 33, HPLout/HPRout Level control is not recommended to use as volume control on the fly as following ====.
However, customer's usage as CASE-B : use HPLout/HPRout Level Control is problem ?
Customer says it seems no problem using HPLout/HPRout Level control on the fly and its better than CASE-A...
Would you please give your opinion?
Customer hope to have your approvement.
===
d/s page 33
Note that this output level control is not intended to be used as a standard output volume control. It is expected to be used only sparingly for level setting,
that is, adjustment of the fullscale output range of the device.
====
*CASE-A Previous*.....Problem ( zipper noise )
P0 Reg47 DAC_L1 to HPLOUT Volume Control Register: change 0 to -46dB on the fly
P0 Reg51 HPLOUT Output Level Control Register: fixed (6dB fixed)
P0 Reg64 DAC_R1 to HPROUT Volume Control Register: change 0 to -46dB on the fly
P0 Reg65 HPROUT Output Level Control Register: fixed (6dB fixed )
*CASE-B Corrective action*
P0 Reg47 DAC_L1 to HPLOUT Volume Control Register: change 0 to -40dB on the fly
P0 Reg51 HPLOUT Output Level Control Register: change 0 to 6dB on the fly
P0 Reg64 DAC_R1 to HPROUT Volume Control Register: change 0 to -40dB on the fly
P0 Reg65 HPROUT Output Level Control Register: change 0 to 6dB on the fly
Sorry to bother you again
Best Regards
