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RE: [linrad] The tradeoff of 192 kHz sampling

Hi Kohjin,
> On the other hand the study of the technical specification of the AK5394A
> indicates that the S/N ratio decreases at higher sample rates as 
> a result of
> the expansion of the frequency band. Actually the S/N decreases 
> by more than
> 3 dB that one would expect as a result of a doubling of the 
> sample rate from
> 96 kHz to 192 kHz.

The A/D samples at some much higher frequency and then it filters
and resamples at 96 or 192. Without taking the time to read through the
data I assume the noise floor is not flat, it probably increases
with frequency just like the AK4524.

There is a good readon to increase the bandwidth, with twice the bandwidth
Linrad will be even more efficient in removing qrn. At 192 kHz there is
a good chance that one can remove static rain more or less completely.

For the blanker to work well there is no reason th have the same low
noise floor over the entire frequency range and if only the center
100kHz region is displayed I am pretty sure the noise floor will
be at the same low level in both 96 and 192 kHz mode.

Another thing is that the WSE RX2500 filters should be modified to
allow more bandwidth. This should be pretty straight-forward.


Leif  /  SM5BSZ