[time-nuts] yet more RFTG thoughts

Rich and Marcia Putz rputz at bnin.net
Tue Feb 20 18:32:54 EST 2007


Hi All;
To answer a question first. I believe PLDENB likely means programmable logic device enable. Right next to that header is an Altera Max7000 series device. What we dont know is, when enabled does that mean the device just wakes up, or does it mean the device is opened to be reprogrammed. 
I am still interested if anyone else has measured the voltages on TP400 to see if anything is present other than +5 volts. I have not found any mode that makes my RFTG produce any voltages other than the 5volts. The DAC appears to be dormant. You can roughly follow the traces from the DAC near TP400 over to the EFC line to the oscillator. The jumpers W11-W12 is the EFC line to the osc, I measure much less than 1 volt, I would imagine with the unit working, it would be somewhere around 3-4 volts! 
Again I have to say I am running the RFTG-m stand alone, as I have no RFTG-RB to go with it.
So as was mentioned earlier , when a 10 Mhz signal appears at the input do things start happening, I applied 10 Mhz from my HP5334, but perhaps I didn't have enough level, and thats begs a second question; if 10Mhz is present there then why would the GPS side be needed at all, unless the RFTG-m is somehow comparing the two signals and picking the one in closest agreement to GPS. Who knows?
On a side note, I did a google search on RFTG and one hit was a guys resume describing how he designed RFTGs for HP. I'll let a younger and more daring person search the guy out and contact him, hi-hi! 
Rich


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