[time-nuts] GPS first LO need to be locked?

paul swed paulswedb at gmail.com
Sat Apr 1 11:18:37 EDT 2017


Thanks everyone but I am working on an austron 2201a so all the discussions
on modern methods won't help. Whats is interesting is indeed the 2201 down
converts to 80KHz and the does sample in an IQ fashion. Its all discreet
chips and such.
Easily traceable and logical.
I think I have what I asked for and am experimenting with active mixers and
IFs made of minicircuit gain stages.
I am using a commercial antenna with 34 db of gain. It says 50db I question
that.
But lots of gain to a HP IAM 81008 active mixer low drive LO. Then a 40db
at least 75 MHz IF. (Pretty sure this is overkill.)
The LO is a HP 8660c for now. Locked to a TBolt.
Thats the reason for the question. I can shift the 8660 to the ausytron 10
MHz.
Regards
Paul.
WB8TSL

On Fri, Mar 31, 2017 at 7:47 PM, Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
>
> There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s
> then (re) sampled from there. The “LO” in this case would down convert to
> the low IF ….
>
> Bob
>
> > On Mar 31, 2017, at 6:08 PM, Magnus Danielson <
> magnus at rubidium.dyndns.org> wrote:
> >
> > God natt Attila,
> >
> > On 03/31/2017 11:29 PM, Attila Kinali wrote:
> >> God kväll Magnus,
> >>
> >> On Fri, 31 Mar 2017 21:19:00 +0200
> >> Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
> >>
> >>> Still fills the function of LO, as the sample and hold operates as a
> >>> mixer and the fold-down can be seen as an overtone mix followed by a
> >>> sampling of the mix product, so well, it's about the same thing.
> >>
> >> "Harmonic mixer" is the word you are looking for :-)
> >
> > Not necessarily. It could be a locked oscillator too.
> > Harmonic mixer is another way to go.
> >
> > Cheers,
> > Magnus
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