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TLV320AIC3204: TLV320AIC3204 Rate Matching

Part Number: TLV320AIC3204

Hi Team,

We’ve been debugging an issue with trying to match the codec output rate with our Bluetooth A2DP streaming rate (which should ideally be 44.1 kHz).

More specifically, we’re using register values corresponding to 16 MHz MCLK setting of 44.1 kHz section of Table 2-27 in TLV320AIC3204 Application Reference Guide.

Unfortunately, the A2DP input rate is lower than 44.1 kHz causing underflows on the output and corresponding audio artifacts.

So, to rate match to it, we modified just PLLD value from 2920 (in the table) to 2779 with all other settings unchanged. With this, we were able to rate match nicely with the BT input audio (no more underflows or overflows).

But now there’s an overwhelming hiss on the codec output which is not acceptable from audio quality perspective.

The hiss doesn’t happen with PLLD value of 2920.

Can you shed some light on what might be causing the hiss on the codec output when we change just the PLLD setting?

We need to fix this to be able to rate match for a Bluetooth use case.

Best Regards,

Wilson - TI Medical/ Health & Fitness Team

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  • Hi, Wilson,

    Thanks for the problem description. Changing the PLL coefficient will affect the internal clocks, which could lead into issues with the device processing and performance. Is it possible to adjust the BT module sampling rate?, maybe 32KHz or lower could be used.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

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