Hi Said, It seems there are indeed many ways to kill a cat. What happens to the close-in phase noise using this method?
Cheers, Stephan. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of [EMAIL PROTECTED] > Sent: 01 March 2007 03:39 PM > To: [email protected] > Subject: Re: [time-nuts] Low noise frequency multiplication > > > In a message dated 2/28/2007 15:20:56 Pacific Standard Time, > [EMAIL PROTECTED] writes: > > It describes a way in which an analogue odd-order frequency multiplier > could > be built cheaply with superior noise characteristics. This circuit that > is > described is really simple and quite ingenious. Unfortunately, I would > like > to multiply by 10 (an even number) so I still need a way to at least > multiply by 2. Commercial low-noise multipliers are in general much more > expensive than my OCXO. So now I am curious if there is an easy and > reliable > way to get a 10MHz sine up to 100MHz without degrading the phase noise. > > > > Hi Stephan, > > one way to do it is using a DDS, say one of the new 1Gs/s 14-bit DAC > units > from Analog Devices: > > bring the 10MHz up to 1GHz using a 1 to 100 PLL and a low-phase noise 1GHz > VCO or 1GHz crystal (these 1GHz low-jitter crystal Oscillators have > recently > been advertised). > > Then use the DDS to generate 100MHz at 1Gs/s. > > Noise floors of <-155dBc/Hz can be easily achieved with a good DDS. You > will > need is a low pass at around <400MHz to remove aliases etc. > > One advantage of this is that you can generate essentially any frequency > in > <1Hz steps up to about 400MHz (without having a frequency-dependent noise > floor on the DDS output). > > You could get a DDS eval board from Analog to do this. > > This is essentially what the Jackson-Labs FireFox Synthesizer does. > > bye, > Said > <BR><BR><BR>**************************************<BR> AOL now offers free > email to everyone. Find out more about what's free from AOL at > http://www.aol.com. > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
