[hpsdr] Mercury sampling rate

[Alberto I2PHD]

Phil Harman wrote:
>  
> We sample at 122.88MHz since that divides evenly to standard sound card 
> frequencies.  This does need updating since we will be able to achieve 
> 2MHz of displayed bandwidth using the current USB2 interface to the PC.
>  
> 73's Phil...VK6APH

May I ask the rationale behind that ? The data sampled by the ADC are of course not meant to be passed through a sound 
card after the decimation... they are already digital. And for the output you need always to use a fractional resampler 
as you cannot have any guarantee that the sampling rate of the output sound card is an *exact* submultiple of the 
downsampled rate. And, once you have accepted the need of a fractional resampler, then any ADC clock frequency can be 
used.

Or maybe I am missing part of the picture ?

73  Alberto  I2PHD


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