Burt I. Weiner wrote: > It would seem the most jitter free way to do it would be to simply > multiply it up like we used to do. Some reasonably Hi-Q LC circuits > could make a nice flywheel and filter out other signals at the same > time. Once you have it to the desired signal frequency you could > condition it to clock your DDS.
Some experience here. At Zeta Labs, we made a lot of money building such multipliers. It is surprisingly hard to do it correctly and get low phase noise. At HP, the X6 multiplier to 60 MHz in the 5065 and the X9 multipler in the 5060/1 were full employment plans for production engineers, especially if they were operating under the Peter Principle. HP definitely knew less than Zeta about these things. The two examples of doing it right at HP were the 8662A and 5071A which had doubler chains. I never heard a peep from the production engineers about the 5071A doubler chain that I designed. It just worked. Period. The doubling was accomplished by wiring the LO and RF ports of an ASK-1 mixer in series and driving it with a very well filtered low distortion sine wave (important) at about 10 mW. The output filtering was just a ladder of parallel resonant tanks in shunt and series resonant tanks in series. The Q of the tanks was fairly low. I used a fair number of them to get enough filtering. Not a few high Q tanks as you typically see. There were no (zero) adjustments. Rick Karlquist N6RK _______________________________________________ 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.
