[time-nuts] WWVB PM Time Questions

Wed Aug 19 12:48:15 UTC 2020

Ray,

I'll answer your question as I've done this.  The d-psk-r's intended use is
to remove the bpsk from the WWVB carrier for the purpose of allowing older
WWVB receivers to recover phase info from the carrier and it works very well
for that purpose.  But, it can also be used, as you are trying to do, to
generate "something similar" to the WWVB BPSK signal by feeding it 60 khz
and letting the mixer do the phase modulation.  I've done it, and it works.
But there would certainly be some differences between that signal and the
"real" WWVB BPSK.  For one, the real WWVB signal has phase coherence between
the 60 khz and the timing of the phase flips.  You won't get that with the
d-psk-r as it's not necessary for it's intended purpose.  Obviously WWVB
also has the AM component too so that would be missing if using the d-psk-r
to modulate a carrier.

But depending on your intended use, I see no reason that using the d-psk-r
as a "re-psk-r"  shouldn't work just fine. 

If you're putting a sine wave in to the mixer on pin 8, you should be seeing
a sine wave out on pin 1.  It's as simple as that.  And that sine wave
should shift 180 degrees (invert polarity) if you flip the polarity of the
bias on pins 10 and 15.  If you don't have any DC bias on pins 10/15 I'm not
sure how much signal would pass through the transformers though I don't
think it would be much as neither pair of diodes would be conducting.

Good luck,

Rodger  

-----Original Message-----
From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of
rcbuck at atcelectronics.com
Sent: Wednesday, August 19, 2020 2:20 AM
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>
Subject: Re: [time-nuts] WWVB PM Time Questions

Paul,

Yes, I built the d-psk-r per the schematic. However, I think I did not
understand how it actually worked. I was expecting it to be able to
duplicate the WWVB sine wave signal with the phase reversal present when the
PM data bit changed from a 0 to 1 or 1 to 0. I have a 60 kHz sine wave going
into pin 8 of the mixer transformer. I expected to see a sine wave out of
pin 1.

However, I looked at the code again and it appears the "LO" port of the
mixer is only driven one per second. There is no steady drive to the "LO"
port so there cannot be a sine wave out of the "IF" port. Is that correct?

Or should there actually be a 60 kHz sine wave coming out of pin 1 on the
mixer? If so, something is wrong with my d-psk-r. I am not trying to use it
with any kind of receiver. I just want to see the sine wave on my scope.

Ray,
AB7HE

-------- Original Message --------
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed <paulswedb at gmail.com>
Date: Tue, August 18, 2020 12:19 pm
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>

Ray I would tend to agree but I actually am unclear on the context.
Did you actually build a d-psk-r?

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