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PCM5122: PurePath - PCM5120 ROM - Disable aliased Biquads for Left / Right (1,2 & 3,4 & 7,8)

Part Number: PCM5122

Hi,

I'm trying to implement a HPF on the PCM5122 using PurePath and the built in ROM.

The HPF works as expected, but I'd like to only apply the filer to a single channel. On the ROM each right channel Biquad is aliased to the Left channel Biquad, meaning any changes I make apply to both.

Is there any way to apply changes to only a single channel with the PCM5122?

Thanks

  • Hi,

    Thank you for your query. The responsible engineer for this part is not available at this moment due to holidays. He will get back to you soon.

    Regards,
    Applications Engineer, Precision DACs
  • NZIceMan,

    My understanding is that there isn't any way to get this done on the PCM512x sets of devices. These devices only allow for modifications to the filter coefficients, but you can see in Table 21 the filters are grouped in a symmetrical fashion - so for example Biquad 1 and 2 are grouped, Biquad 3 and 4 are grouped, Biquad 5 and 6 a grouped, and biquad 7 and 8 are grouped. In Figure 57 these end up being symmetrically oriented in both left and right channels.

    I think on PCM514x family this type of non-symmetrical configuration would be possible since you also would have access to the instruction register of the miniDSP but I'm not sure it would make sense or be useful since the coefficient pairings for the previously mentioned filter groups would still exist.