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Sampling PCM4220 channels

mike16284
Prodigy 20 points
Other Parts Discussed in Thread: PCM4220

Hi all,

Are the left and right channels of PCM4220/4222 sampled simultaneously? In other words, is there any difference between left and right modulator outputs, provided left and right inputs are tied together and fed by e.g. sine wave? I'm planning to use this ADC in a data acquisition system...

mike

  • 0
    TI__Intellectual 2810 points

    Hello Mike,

    The left and right channels are sampled simultaneously. If the same input signal is fed to both the left and right analog input of the PCM4220/4222, the the data output by the multi-bit modulators will be the same. However, the PCM data output is 24-bits, and there will be differences in the least significant bit of the data due to dithering used within the conversion process. Differences in external noise coupled or injected onto the left and right analog input pins can also cause a few LSB difference between the left and right channel output data. Attention in detail to PCB layout,  as well as matching in external front end circuitry, can minimize this error.

    - Bob Martin

     

  • 0 in reply to Bob Martin
    Prodigy 20 points

    Bob, thank you for reply!  All I need to know is that  I will not get a phase shift between left and right digital signals caused by non-simultaneous sampling (as it would be in the "sequencing" converter).

  • 0 in reply to mike16284
    TI__Intellectual 2810 points

    Mike,

    There will be no phase shift between the left and right channel outputs.

    - Bob