Phase Noise - RF Cafe Forums

RF Cafe Forums closed its virtual doors in late 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2012, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts. Here is the full original RF Cafe Forums on Archive.org

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satish.1979

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

Captain

Joined: Tue Oct 03, 2006 3:03 am

Posts: 11

Location: India

Q1

why flicker noise contributes to the phase noise, not the thermal noise in oscillators?

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Stephen

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

Captain

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!

www.srftechnologies.com

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satish.1979

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

Captain

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

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IR

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

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm

Posts: 373

Location: Germany

Hello,

There are some nice articles in www.rfic.co.uk website:

https://www.odyseus.nildram.co.uk/RFMicr ... llator.pdf

https://www.odyseus.nildram.co.uk/RFMicr ... Basics.pdf

https://www.odyseus.nildram.co.uk/System ... eNoise.pdf

Good luck!

_________________

Best regards,

- IR

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Stephen

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

Captain

Joined: Wed Jun 21, 2006 8:33 pm

Posts: 21

Location: Queen Creek, Arizona

IR,

That is a great website. Thanks for the link; I had never stumbled across the site previous.

_________________

CMOS RF and Analog ESD Specialist!

www.srftechnologies.com

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fred47

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

General

Joined: Wed Feb 22, 2006 3:51 pm

Posts: 104

Hi!

One of the most available books on oscillator design is by Randall Rhea, entitled Oscillator Design and Computer Simulation.

Good Luck!

Fred

Posted  11/12/2012