Rex wrote: > On Tue, 26 Dec 2006 22:06:28 -0600, "Bill Hawkins" <[EMAIL PROTECTED]> > wrote: > > >> What's all this about 15 MHz out? >> >> Bill Hawkins >> > > I have an FRS-C rubidium (10 MHz) that I bought a couple years ago. It > came in a metal box that also contained a circuit board that provided 3 > TNC output connectors. Two of those had 10 MHz square wave output. One > provided a strong (24.3 dBm into 50 ohms) 15 MHz sine wave output. > > The board somehow used the 10 MHz from the rubidium to generate a 15 MHz > sine. I never figured out exactly how they were doing this; the board > had an an Altera EP610PC-25T PLD doing most of the interesting stuff. I > now suspect my box must have been for a similar setup to the Lucent > application. > > In the FRS box I noticed a 15 MHz filter on the board. If you look at > John's picture rftg-m-xo-7.jpg, the metal can in the top-center (not the > Efratom oscillator) is a 15 MHz filter. > > > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > Rex, Bill
The simplest way of generating a 15MHz output signal from a 10MHz input signal, is to divide the 10MHz by 2 using a flipflop and then extract the 15MHz 3rd harmonic component of the 5MHz square wave output of the flipflop with an analog bandpass filter. Bruce _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts