Hello!
With the recent excellent firmwares by DiSlord where the ADC is on the 192kHz sampling frequency we now have very good (very low) noise floor level.
As I read DiSlord's plans - he wants to make the IF higher than the current (recent?) 12kHz, he sees some further advantages in that move.
However, as the LPFs (or are them simplistic BPFs?) after the mixers are just 6dB/octave (a single RC-network), is it good indeed to bring the to be digitised signal's spectrum closer to the sampling frequency? Now the 12kHz IF is reasonably far/low away from the ADC's 192kHz. Making IF equals to 28kHz would (as I see it) create more artifacts from the unfiltered HF-noises in the IF signal.
I think the IF should be related to the ADC's sampling frequency - the sampling frequency should be an even multiple of the IF value. The recent 12kHz is exactly one sixteenth of the 192kHz. I guess - untill the LPF is made more steep - we should not increase the IF value.
Please comment.
Anton
