[time-nuts] WWVB BPSK Receiver Project? (fwd)

[Marek Peca]

> I've designed filters for datacom chips. I know filtering. My point is 
> the original author is making some assumptions in the design which are 
> not stated.

Yes, my fault, I didn't write it properly, so by a "ferrite rod" in 
context of DCF/WWVB reception, I meand a "ferrite antenna in an LC tuned 
circuit".

Apologies for all who have been confused.

> What I don't have a lot of hands on experience is with open circuit 
> magnetics. (I do with closed circuit magnetics.) But I claim if the 
> ferrite rod antenna is not capacitively loaded to resonate at the comm 
> frequency, then there isn't significant group delay error.

Yes, see above. I meant an LC circuit, containing the ferrite rod antenna 
as the L.

> The antenna will have a natural resonant frequency comprised of the 
> inductance and parasitic capacitance. But this represents an upper 
> frequency limit. So simply operate below resonance and the group delay 
> error is minimized. Filtering can be done following the preamp that 
> connects to the antenna, and thus will not interact with it.


Thank you for your understanding.
Marek