[time-nuts] Homebrew WWVB TX simulator?
Bob Clements
time&nut* at clements.org
Tue Sep 14 21:49:14 UTC 2010
Randall said:
Circuit Cellar did an article.
Feburary 2010 #235 Page 38.
This was a WWV simulator for a 2 part article the 2nd being a receiver.
73s
Randall ZL2RJP
Yup, I read that. It didn't have the RF part of the TX.
Magnus said:
If you don't need a precision carrier, but rather a signal good
enough for rough testing then you should not need to do that
much other than cooking up a 60 kHz sine oscillator (maybe a
simple cos/sin oscillator on op-amps will suffice) and let
either a CMOS switch (4066) do the AM-modulation by shorting a
resistor or enabling an additional resistor-path into a summing
op-amp. Should not consume that many parts. Maybe add some
damping stages such that levels can be controlled. Maybe a PIC
to do the modulations trains and a serial interface to set it
up. In all about 3-4 chips. Should not be too hard.
Cheers,
Magnus
Yup. You're reading my mind. That's nearly exactly what I was
thinking of. I was thinking of buying a canned oscillator
from someone. Digikey and Mouser don't seem to have that
freq, but Intl Crystal will custom-order one for you.
Of course, one could go whole hog and put in an ethernet module
and send the bits from a server. And add the nice display.
And a pushbutton to switch between receiving the real signal
and generating the local one and turning on the 60 kHz.
I was just wondering whether anyone had built some version of the
hardware so I don't have to.
Tnx all,
/Rcc
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