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
