[time-nuts] WWVB d-psk-r down conversion method

paul swed paulswedb at gmail.com
Tue Sep 23 15:54:04 UTC 2014


Wow. What 8 hours can do for responses.

Great comments and appreciated. A piece of the puzzle appears to have
gotten lost from the start of the process.

This down converter system. Only detects phase change. It is not intended
to be a phase locked oscillator system that replicates what the old radios
have.

Its output flips a signal path to invert or not invert the incoming wwvb
signal that feeds the old radios.
There is no need for an instantaneous response in the flip circuit. .3-.5
seconds seems fine for the old radios. Want to see if I can get down to
.1-.2 sec.

Pretty sure from what I have seen so far there is no need to lock the LO
nor must it be some precise offset of 100 Hz or anything else.
In watching this on a scope with a stable local 100 Hz reference not locked
to anything. The phase changes were obvious and useful.

One of the comments in the thread was that you could use a good local
reference and adjust for the LO drift. I do believe thats the case. I am
pretty good at dividing in decades. ;-) But getting ahead of the other
criteria. Simple as possible.
OK time to fix the HP3335a that failed. Lost my LO for the moment.

Regards
Paul.
WB8TSL



On Tue, Sep 23, 2014 at 7:37 AM, Bob Camp <kb8tq at n1k.org> wrote:

> Hi
>
> Actually stability isn’t the main problem with the progamables. The issue
> is usually phase noise ad spurs. Often they use odd multi modulo divides
> rather than a PLL. That gives them a low cost chip, but the output spectrum
> is pretty poor. Figuring out if you have a “bad one” or not is tough from
> many data sheets. It’s rare that cheap XO’s come with phase noise and spur
> plots.
>
> Bob
>
> On Sep 23, 2014, at 12:04 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
>
> >
> > paulswedb at gmail.com said:
> >> Did try lots of frequencies and divider math to come up with a simple LO
> >> scheme for 61 or 59 KHz. Messy.
> >
> > There are companies that will make a crystal or oscillator at any
> frequency
> > you want at a not silly price.  Delivery is not overnight.
> >
> > Beware: There are several companies selling instant delivery of
> oscillators
> > running at any frequency you want.  They are using a programmable PLL so
> you
> > won't get the stability you expect from a crystal.
> >
> > --
> > These are my opinions.  I hate spam.
> >
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



More information about the Time-nuts_lists.febo.com mailing list