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

paul swed paulswedb at gmail.com
Mon Sep 22 18:15:59 EDT 2014

One of the methods suggested for working with the wwvb psk is down
converting to a lower frequency. When experimenting with NAA I had built a
24 Khz receiver that down converted that signal to a 100 Hz base band.
It was a minor effort to shift it to 60 Khz by changing the LO. I liked
what I saw. Essentially a simple direct conversion receiver with about 42
DB of gain.
The PSK flips at every 1 second depending on the data and is 1/100Hz
delayed from the wwvb flip due to the down conversion process. This makes
the further processing very reasonable in just about any micro.
But the LO is a mess. Not bad if you have an HP3335a as I did till last
week. (Another project to repair) for 100 Hz the LO must be at 60.1 or 59.9
Khz. Or synthesize it etc. Starting to get seriously ugly.
Or jump to a 1 Khz with 59 or 61 KHz. But I hated the idea of mixers and

Any Time-Nuts seen those crystals or oscillators around lately? Seriously
missing from the general haunts.

But turns out and heavens knows why there are plentiful 5.9904 MHz xtals
around. I ordered 5 from Mouser $ .46 ea.
5.9904/100 = 59.904 as a LO and suspect it can be moved to the correct
frequency not that it has to be.
Not sure there is a real need to lock the LO at all.
So an exciting bit of news.

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