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Phase Noise - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.

Post subject: Phase Noise Posted: Tue Oct 03, 2006 9:45 am


Joined: Tue Oct 03, 2006 3:03 am
Posts: 11
Location: India
why flicker noise contributes to the phase noise, not the thermal noise in oscillators?


Post subject: Posted: Tue Oct 03, 2006 10:11 am


Joined: Wed Jun 21, 2006 8:33 pm
Posts: 21
Location: Queen Creek, Arizona
Both flicker and thermal noise increase the phase noise. The issue is that flicker noise in MOS devices, can be very large, upto the corner frequency (the frequency at which flicker and thermal noise have equivalent magnitudes). In MOS devices the corner frequency can extend to the low the high KHz or low MHz, while in bipolar it usually stays below the low 100's of Hz.

Ergo, because flicker noise tends to have much larger magnitudes, especially at lower frequencies, many designers choose to ignore thermal noise and state that flicker is the only phase noise contributor. This is in fact a mistake; its simply that Flicker noise tends to dominate. But both contribute to phase noise degradation, its just a question of how much.

CMOS RF and Analog ESD Specialist!


Post subject: ThanksPosted: Wed Oct 04, 2006 2:05 am


Joined: Tue Oct 03, 2006 3:03 am
Posts: 11
Location: India
Hello Stephen

Thanks for your brief explanation.
Now I am clear about the phase noise in oscillator.

suggest me some books or articles on oscillator design

Have a nice day


Post subject: Posted: Tue Oct 10, 2006 6:40 am

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany

There are some nice articles in website: ... llator.pdf ... Basics.pdf ... eNoise.pdf

Good luck!

Best regards,

- IR


Post subject: Posted: Wed Oct 11, 2006 1:41 pm


Joined: Wed Jun 21, 2006 8:33 pm
Posts: 21
Location: Queen Creek, Arizona
That is a great website. Thanks for the link; I had never stumbled across the site previous.

CMOS RF and Analog ESD Specialist!


Post subject: Book on Oscillator DesignPosted: Thu Oct 19, 2006 5:51 pm


Joined: Wed Feb 22, 2006 3:51 pm
Posts: 104
One of the most available books on oscillator design is by Randall Rhea, entitled Oscillator Design and Computer Simulation.

Good Luck!

Posted  11/12/2012
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