Hi, could recommend some equipments to measure phase noise?

Hi, could recommend some equipments to measure phase noise?

For very low phase noise like -160 dBc/Hz with some offset frequency.

Thank you.

The best option is the VCO/PLL analyzer from Agilent:
http://www.home.agilent.com/USeng/na...879446/pd.html

A cheaper way is to use a good Spectrum Analyzer that has Phase Noise measurements capabilities as PSA from Agilent:

http://www.avalontest.com/e-store/pr...12157493871983

or FSE from R&S:

http://www.rohde-schwarz.com/WWW/Publicat.nsf/article/n163_fse/Sfile/n163_fse.pdf

HP 11729c + HP 8663A

or HP 3048A phase noise measurement

160 dBc/Hz at what offset frequency?

at an offset frequency roughly 20MHz

160 dBc/Hz is low, but at 20 MHz offset it is readily obtainable in the measurement schemes the others have stated above.

You can use a good spectrum analyzer that has a phase noise measurement utility.

Alternately, you can use a phase noise measurement system in conjunction with a tunable frequency synthesizer that is used to downconvert the unit under test to baseband. This is a more complex measurement, but is more accurate. The tunable frequency synthesizer that you use in this method has to have phase noise that is at least 10 dB better than the phase noise level you are trying to measure to.

biff44

you cannot use spectrum analyzer for Phase noise measurement of 160 dBc, it's limited by its dynamic range not more than 155 dB in high end Agilent or R&S.
There is a possibility to do that with spectrum + notch + LNA setup (filter the carrier and amplify the noise with LNA), but it's a complex setup.
Latest VCO/PLL meter has this capability, but it's at the limit of its performance, can obtain it only with corrections (already implemented).

It's important ot note if you're interested in phase noise effects only or also to am/fm effects: with spectrum you cannot distinguish phase noise from am/fm conversion, you measure both; with dedicated phase noise testers, as they are based on a completely different way of measurements, you measure only phase noise.
I hope it can help.
Mazz

Mazz, you are right. I just tried a manual measurement on an older HP S/A, and all I got down to was -135 dBc/Hz while keeping the carrier uncompressed. Agilent says they can do -145 dBc/Hz at 1 GHz using the phase noise measurement utility:
http://www.home.agilent.com/USeng/na...881858/pd.html

I guess you have to bite the bullet and rent a full blown phase noise measurement system, OR like Mazz says, switch in a notch filter and calibrated RF amplifier when you are measuring noise at 1 MHz+ from the carrier.

It not interesting to measure phase noise -160 dBc/Hz at 20 MHz offset from the carrier it so far, and it is a noise floor.
we measure oscillator phase noise from about 10 KHz.