The 6 mixer scheme was my first thought for lowest PN. That way you do not get 20logN, but you just get the RMS sum of the noise power each time. That would be 3 dB to get to 20 MHz, and, each time the sum becomes less than 3 dB, as the highest frequency dominates. It would only degrade approximately a total of 10 dB vs. the 17 dB from a regular times 7. Regards - Mike
Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bill Hawkins Sent: Tuesday, December 21, 2010 2:55 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] What is the best way to multiply a 10 Mhz So, two doublers for 40 MHz and a tripler for 30 and then mix to get 70? What happens to phase noise when you do that? Is it as bad as a PLL? Seems like you ought to get adequate harmonic rejection. What about six mixers to get 20, 30, 40, 50, 60, and 70 MHz? Chips and tank coils are cheap, no? Bill Hawkins -----Original Message----- From: Burt I. Weiner Sent: Tuesday, December 21, 2010 1:39 PM 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. Am I missing something here? Wouldn't be the first time, ya know! Burt, K6OQK >Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz > signal? > > >On 21/12/10 16:35, Stephen Farthing wrote: > > Hi everyone, > > > > I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at > > 70 Mhz. Has anyone tried this? > > > > Regards, > > > > Steve G0XAR _______________________________________________ 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. _______________________________________________ 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.
