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PCM4202: Setting questions about digital filter and processing delays

Part Number: PCM4202
Other Parts Discussed in Thread: PCM1804,

Hello team,

I received a question from the customer about settings for PCM4202 and PCM1804.

(1) Changing digital filter settings

Looking at the filter characteristics, it seems that the PCM4202 and PCM1804 both have a digital filter setting that limits the bandwidth to 48 kHz or lower when FS=96 kHz. Is it possible to set a digital filter that limits the bandwidth to 24 kHz or less when FS=96 kHz, which is the same bandwidth as when FS=48 kHz? If possible, the customer would also like to know how to change the settings.

*Related descriptions (PCM1804 datasheet p13-14 Figure 17, 21) (PCM4202 datasheet P7-8)

(2) How to reduce signal processing delays

For both PCM4202 and PCM1804, is there a way to reduce the amount of delay in signal processing between input and output when FS=48kHz?

Best Regards,

Ryotaro Fukui

  • Hello Ryotaro,

    Thanks for posting again.

    1. Unfortunately it is not as simple as just changing filters, the filters are set-up in a way to accommodate to how signa-delta modulator ADCs you cant switch around the digital filters with different sampling rates they were not meant for.

    2. There is nothing really can be done about the delay when using 48KHz.

    Maybe take a look at our newer models of Audio ADCs that have more flexibility and efficiency:

    www.ti.com/.../products.html

    Best Regards,

    Carson