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LM97593: LM97593

Carlos Ilarregui
Prodigy 50 points
Part Number: LM97593

I need to know what is the number of effective bits at the serial output of this device when configured in all three fixed point modes (rounded 16-bits, rounded to 24 bits, and full 32-bit resolution) and using the set of filters included in the data sheet.

What is the improvement in the noise floor when moving from 16 to 24 to 32 bits?

Figure 60 suggests that although the coefficients are 16-bit, the output of the FIRs are 21-bits wide

Thank you

  • 0
    TI__Mastermind 44560 points
    Hi Carlos
    I am looking into your questions. I should have a more detailed response sometime tomorrow.
    Best regards,
    Jim B
  • 0 in reply to Jim Brinkhurst1
    TI__Mastermind 44560 points
    Hi Carlos
    The serial output data modes only support 8-bit truncated, 16-bit rounded and 24-bit rounded fixed point modes.
    Given the basic SNR maximum (given datasheet conditions) of around 82dB the 16-bit mode is just enough to handle this SNR without degradation.
    However if the DVGA/AGC feature is used the device has extended dynamic range. In this case the 24-bit mode is recommended to ensure full performance. If the DVGA/AGC is not used then 16-bit mode should suffice.
    The width of the coefficients does not limit the noise/resolution of the filters. The coefficient width only has an impact on how precisely the transfer function of the filters can be tuned.
    Best regards,
    Jim B