[time-nuts] Near-perfect chip for Loran-C frequency receiver

[Carl Walker]

On Fri, 2008-07-04 at 01:02 +0200, Magnus Danielson wrote:
> > The analog side would need to allow for those signals also then.
> 
> Naturally. The antenna-amplifier design will need to be more wideband
> oriented. Should not be too hard thought.
> 
> Cheers,
> Magnus

I respectfully disagree; while making the wide-band receiver is an easy
task, you now have a family of unrelated signals - often of widely
varying signal strength. Once any of those signals becomes large enough
to drive the receiver non-linear, you rapidly run into issues.

AGC to maintain linearity isn't practical in this case - since reducing
overall receiver gain to compensate for one large signal - like WWVB if
you're close by that one transmitter - will potentially drive down the
gain for desired LORAN and other signals to the point where you can't
acquire and track many of the weaker but never the less desired signals.

There's more than meets the eye initially when you attempt a receiver
design of this type - at least as far as the analog section goes. Once
it becomes 1's and 0's it's all straight forward - at least as far as
this old ex-analog guy is concerned ;-)

-Carl