Henk - Did you try to measure the PN out of the oscillator directly without the buffer amp (U1)? Also, what is the voltage from V1? Is it also 12V? HNY - Mike
Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Henk ten Pierick Sent: Tuesday, January 01, 2008 7:25 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] xtal oscillator phase noise On Dec 30, 2007, at 3:42, Bruce Griffiths wrote: > Henk > > The 30dB/decade phase noise slope could be the result of the effect of > low pass filtering a power supply or reference source that has > significant flicker noise. The reference used is an ADR455. I have not seen references significant better. Suggestions? > Lack of local RF feedback and /or high dc gain from base to > collector in > BJT buffer stages can produce significant flicker phase noise. I have now doubled the dc voltage for the oscillating transistor for the reduction of junction capacitances. It had no result on phase noise. Is low hfe better for phase noise? Henk _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.