Hi Fred, I like the Crystek CVHD parts, and MtronPTI also has a number of good ones. bye, Said In a message dated 2/2/2011 19:50:10 Pacific Standard Time, [email protected] writes:
Hello Said, > Low Noise 100MHz VCXO's are readily available at mouser and digikey (so > are 80MHz units), and programming the ADF4002 is straight forward with the > help from the AD online tools. It can be bit-banged with any microcontroller. Any particular ones that are in stock at digikey/mouser that you would recommend? regards, Fred ----- Original Message ---- From: "[email protected]" <[email protected]> To: [email protected] Sent: Wed, February 2, 2011 9:12:38 PM Subject: [time-nuts] Fwd: 10MHz to 80MHz frequency multiplier suggestions Hello Raj, our ULN-1100 and ULN-2550 GPSDO's use a 100MHz VCXO locked to the 10MHz OCXO via an ADF4002 PLL with less than 40Hz bandwidth. After careful optimization of the layout and the loop filter, the phase noise results are quite excellent at 100MHz, see the attached plot. The plot shows two versions of the PLL loop filter from the design phase of the products, one has been more optimized. You can see that the noise floor is almost -170dBc/Hz at 100MHz. You get the best of two worlds: the absolute frequency accuracy of the GPSDO, and the very low phase noise of the VCXO above the PLL bandwidth. It is clearly visible that the VCXO phase noise inside the loop bandwidth is actually also reduced by locking it to the 10MHz OCXO (the PN curve below the loop bandwidth frequency of ~30Hz would just continue going up without the PLL) Low Noise 100MHz VCXO's are readily available at mouser and digikey (so are 80MHz units), and programming the ADF4002 is straight forward with the help from the AD online tools. It can be bit-banged with any microcontroller. bye, Said From: Raj <[email protected]_ (mailto:[email protected]) > Date: January 31, 2011 21:11:46 HST To: Discussion of precise time and frequency measurement <[email protected]_ (mailto:[email protected]) > Subject: Re: [time-nuts] 10MHz to 80MHz frequency multiplier suggestions Reply-To: Discussion of precise time and frequency measurement <[email protected]_ (mailto:[email protected]) > I was contemplating the same thing. I fed the output to a bifilar transformer and diode doubler and got good results. I have to add an amp and double it again twice more. It is still on breadboard. The object was to multiply the error 8x and compare. Probably a PLL locking to 80 Mhz will retain the long term accuracy of the TBolt reference. Raj, vu2zap At 31-01-2011, you wrote: I'd like to convert the 10MHz output of a Thunderbolt to 80MHz: it should be used as a 3.3V clock for an A/D converter. Even if I have already taken a look to documentation from KO4BB and Wenzel regarding frequency multiplier, I'm asking if you have some more references or even better, some schematics of a working 8x multiplier. . thanks in advance _ Elio Corbolante. _______________________________________________ time-nuts mailing list -- [email protected]_ (mailto:[email protected]) To unsubscribe, go to _https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts_ (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. _______________________________________________ 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.
