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| Crystal Reference Oscillator Design - RF Cafe Forums | ||||||
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Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
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Below are all of the forum threads, including all the responses to the original posts. darcyrandall2004 Post subject: Crystal Reference Oscillator Design. Posted: Sun Oct 21, 2007 3:25 am Colonel Joined: Tue Feb 27, 2007 6:16 am Posts: 46 Hello, For the sake of learning and my own interest, I have been designing a UHF data radio. Is this correct ? If my carrier freq is 450.325MHz accurate to +/-200Hz Lets say Im using a 20MHz Crystal reference oscillator for my PLL. Then a rough calculation tells me that my crystal must be accurate to within -> 20*PPM*(450.325*10^6)/(20*10^6) < 200 -> 0.44PPM. Where PPM is parts per million. If these calculations are correct, can anyone recommend where I can find a crystal reference ocillator with a TTL or CMOS output, accurate to 0.44PPM? I believe an oscillator from 5MHz to 25MHz would be suitable. FYI my channel width is 25kHz, Im using National's LMx2346. Thankyou Regards Darcy Randall, Perth, Western Australia _________________ Regards, Darcy Randall, Perth, Western Australia Top IR Post subject: Posted: Sun Oct 21, 2007 5:14 am Site Admin Joined: Mon Jun 27, 2005 2:02 pm Posts: 373 Location: Germany Hello Darcy, Your calculation is correct. For such a tough spec as you have a simple Crystal is not good enough. You should use a TCXO. I found an example for one with 0.28PPM and a CMOS output: http://www.valpeyfisher.com/openlink.as ... FTX160.pdf You can also ask for samples and define the frequeny that you need. Please contact the manufacturer for further help. Top darcyrandall2004 Post subject: Posted: Sun Oct 21, 2007 9:03 pm Colonel Joined: Tue Feb 27, 2007 6:16 am Posts: 46 Legend. Thankyou _________________ Regards, Darcy Randall, Perth, Western Australia Posted 11/12/2012 | ||||||
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