At 05:27 PM 10/6/2007, Bill Tippett wrote: >On 10/6/07, Jim Lux ><<mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED]> wrote: > >Rob is/was on this list so I'll let him respond re his >methodology. Whatever it is, he's been doing it for years and all >his other measurements show decreasing phase noise with increasing >frequency offset.
Yes.. that's what one would expect, except with a PLL where the noise inside the loop bandwidth looks flat, until you get close enough to where the reference noise shows up. that is, the phase noise of a PLL source looks like a narrow peak sitting on top of a mesa, with the fall off of both the edge of the mesa and the narrow peak both being about 20dB/decade. Often, you see a hump at the edge of the mesa (if the loop bandwidth is a bit too narrow for the noise properties of the VCO, relative to the reference noise) And, of course, typical PLL loop bandwidths are in the 10s to 100s of kHz range, so a flat phase noise might not be all that unusual. If you had a real quiet reference oscillator, you might not see the rise out of the flat part until <1 kHz away. > BTW the data is for the K3...not the K2. My typo, sorry.. > Here are a couple of other interesting comments from the K3 > designers on Elecraft list: > ><http://mailman.qth.net/pipermail/elecraft/2007-October/074865.html>http://mailman.qth.net/pipermail/elecraft/2007-October/074865.html > >(KK7P DSP designer) ><http://mailman.qth.net/pipermail/elecraft/2007-October/074866.html>http://mailman.qth.net/pipermail/elecraft/2007-October/074866.html > >(N6KR co-owner) > >73, Bill W4ZV James Lux, P.E. Spacecraft Radio Frequency Subsystems Group Flight Communications Systems Section Jet Propulsion Laboratory, Mail Stop 161-213 4800 Oak Grove Drive Pasadena CA 91109 tel: (818)354-2075 fax: (818)393-6875 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20071006/5f2c96db/attachment.html _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
