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Can coarse and fine be used together? For down converter or up converter.

Hello,
I am quite confused because of the following article I read on page 50 of the ad9081 user guide(www.analog.com/.../ad9081-ad9082-ug-1578.pdf) and the fact that only coarse or fine can be selected for the up converter or down converter I encountered in the mxfe jesd204 mode selector tool, otherwise the tool gives an error.

Does this mean that if we consider the dac path for the example in the image below, I can only use fine digital upconversion or coarse upconversion? Can't I use both back to back?

Best.



image
[edited by: jsdqa at 8:54 PM (GMT -4) on 19 Apr 2022]
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  • Hello,

    The 1st cut-and-paste from UG1578 pertains to the Rx data path where it is possible to use the Rx main data path's DDC/Decimation blocks if the decimation factor meets the application requirements...............as well as include the Channelizer path if higher decimation factors (in support of narrow RF RF bands) is desirable or if multi-band processing of two or more narrow RF bands is desirable.  In either case..............the ADC is nominally configured for RF sampling of a "real signal" (as opposed to a "complex signal originating from a RF analog IQ demodulator) in which the IQ demodulation in the digital datapath results in a 6 dB loss of the signal (since only one of the "sidebands" is extracted).  As a result, one can set a digital 6 dB gain block in the final stage of digital processing (i.e. main datapath or channelizer datapath....if used) to compensate for this loss.  When this gain block is set correctly than a full-scale input signal (0 dBFS) appearing at the ADC's input will also appear as a full-scale signal after digital process..........appearing as 0 dBFS on a complex FFT).

    For both the Rx and Tx data path.....................one can use the main datapath only or also include the channelizer data path (if required for multi-band applications requiring different channelizer NCO frequencies  or higher interpolation/decimation factors).

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  • Hello,

    The 1st cut-and-paste from UG1578 pertains to the Rx data path where it is possible to use the Rx main data path's DDC/Decimation blocks if the decimation factor meets the application requirements...............as well as include the Channelizer path if higher decimation factors (in support of narrow RF RF bands) is desirable or if multi-band processing of two or more narrow RF bands is desirable.  In either case..............the ADC is nominally configured for RF sampling of a "real signal" (as opposed to a "complex signal originating from a RF analog IQ demodulator) in which the IQ demodulation in the digital datapath results in a 6 dB loss of the signal (since only one of the "sidebands" is extracted).  As a result, one can set a digital 6 dB gain block in the final stage of digital processing (i.e. main datapath or channelizer datapath....if used) to compensate for this loss.  When this gain block is set correctly than a full-scale input signal (0 dBFS) appearing at the ADC's input will also appear as a full-scale signal after digital process..........appearing as 0 dBFS on a complex FFT).

    For both the Rx and Tx data path.....................one can use the main datapath only or also include the channelizer data path (if required for multi-band applications requiring different channelizer NCO frequencies  or higher interpolation/decimation factors).

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