On 09/14/2010 11:10 PM, Bob Clements wrote:
Has anyone built / seen / bought a small simulator for WWVB? I live near Boston, and the WWVB signal is pretty marginal around here. MSF on the same frequency isn't that far away, and local noise is pretty fierce. So now and then one of my WWVB listeners (like my generally nice Junghans wristwatch) gets screwed up. The firmware writers aren't very cautious, and there's no parity bit in the code. So I have the itch to build a micro-power WWVB to set stuff with, without having to wait overnight for one or more nights. Before I dive into such a project, has anyone done/seen such a thing that I could buy or copy? I've got a WWV/WWVH simulator that I wrote (and announced) back when they were about to replace the Audichron drum machines, and I can start from there if necessary. The hardware part seems a bit more interesting, but for this purpose I don't need to derive the carrier from a GPSDO or my ancient Rb oscilator.
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 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
