phase noise analyzer and phase noise measurement

[jhenderson0107]

Based on the published specifications (https://qsl.net/bg6khc/pn2060c_phase_noise_analyzer.htm), direct phase noise measurements of the PN2060C are limited to <= 200 MHz.  To extend measurement range beyond 200 MHz, an external mixer and high-quality LO are required. 

[hpw]

Anyone can share some test results? 

Best to ask the developer....

and keep in mind as long as it is NOT a TURN KEY solution given or as an optional, even as for 200MHz and above...

that's a pitta, as do not like to search for ALL required parts for simple below 200MHz operation. 

So hidden unknown costs to deal with.

Just my 2 cents

[drew23]

Hi.

I have the earlier PN2060A. It works like the revised one, besides having a lower noise floor.

The PN2060C is pretty straightforward to use. You need a couple of reference OCXOs, but these don't need to be very expensive, that is the point of the cross-correlation technique. The frequency of the reference oscillators depends on the DUT. I have a pair of 10 MHz and a pair of 100 MHz OCXOs. Filters and amplifiers are needed but they too are dictated by the DUT. Battery packs are used to reduce correlated noise.

I have a blog post from a couple of months ago on measuring in the sub-200 MHz range.

I am currently finishing a post on using it with inexpensive downconverters to extend the range into micro GHz. The instrument seems to work well.

Regards Drew VK4ZXI

https://vk4zxi.blogspot.com/2023/07/an-economical-way-to-measure-phase.html

https://vk4zxi.blogspot.com/2024/02/pn2060a-ghz-phase-noise-measurement.html

[KE5FX]

From https://vk4zxi.blogspot.com/2024/02/pn2060a-ghz-phase-noise-measurement.html : "I don't know why AN3899 uses a single reference oscillator for the analyser as two would seem better for cross-correlation."

Since the downconverters are being used to measure a microwave source, the noise at each IF output is determined by the downconversion LO for that channel or the DUT, whichever is worse.  We can assume that the DUT will ultimately dominate, given that the LOs will tend to average out over time, and given that the microwave DUT is usually going to be much noisier than a decent 100 MHz reference OCXO. 

So when the IF is measured by the 53100A, the analyzer typically needs only a single reference OCXO, not a pair.

If you were using a pair of dividers, which allow the DUT noise to actually be improved by the downconversion setup, the story might be different.  E.g. in figure 5.  If dual references hadn't been used there, the measurement error at offsets >1 kHz would have been even higher.

[Gerhard_dk4xp]

Hi, John,

As you know, I'm building a down converter to be used pairwise
to measure X-Band signals with my timepod. It is dual conversion,
1st IF is 900-928MHz with SAWs. It has 2 bands: nervous DC - 3 GHz and
3 GHz-15 or 20 GHz, depending on the mixers and synths  that
happen to be available $TODAY.

Expected DUTS are PLLs or DDS&mixers.
Downconverter REF will be a 100 MHz oven locked to 10 MHz house ref
with adf4002. In a prev. version, the 100->10 MHz divider contaminated
the 100 MHz with its counting spikes, therefore the ADF4002. I hope
the dirt will stay in the PLL chip.

In the pic:

top row from the left:
100 *3 * 3 MHz == 900 MHz 2ndLO, SPI-Interface, High band down
converter, Low noise LT3042 regulator with external power trans.

middle row:
 10-> 100 MHz PLL, 100 MHz xtal oven,  LMX2594/95 synthesizer

bottom row:
5-28 MHz output/2nd down mixer, PIN mux, low band down converter SW..3GHz


Timepod REF will be 1, 4, 8 or 16 MTI-260, sloooowly locked to GPS and
Wilkinsoned together since I'm #inputs-challenged with the timepod.
The guy who sold the Lucent GPS receivers on ebay some years ago
made me an offer for 20 redundancy oven units that I could not ignore :-)
Not removed with hammer and sickle after a life time on a Chinese
telecom tower but still shrink-wrapped.

Do you think I committed systematic errors or oversights?

Cheers, Gerhard,  DK4XP

[KE5FX]

That sounds like a conservative approach, assuming that (1) you use a very low loop BW to lock the 100 MHz OCXO with the ADF4002 and that (2) you use two of them.  Spend a lot of time in ADISimPLL to make sure you are happy with the loop response, as ADF4002s aren't super quiet in-band.  You need both downconverter channels to run at the same frequency for the TimePod's benefit, and that's a good idea in any case, but you want them to behave independently at the Fourier offsets of interest.

As noted above, there is likely to be no need for an exotic reference source at the end of the chain (meaning, at the TimePod REF IN jack).  If you can find an HF OCXO with a white-noise floor near -170, that would probably be fine.

[drew23]

Hi.

The OCXO reference for each local oscillator is also the reference for the analyser. I thought this would reduce the number of noise sources by two.

In the downconverter, I think the main source of noise is the VCO in the PLL which is maybe 20 dBc/Hz worse than the OCXO. However, the two downconveters are not correlated and much of the noise is removed by cross-correlation.

The local oscillator references I have are 10 MHz, just on what was available. The local oscillator signal generators are only about US$160. I am not aware of any other microwave signal generator that is locked to an OCXO at anywhere near the price.

The cost of the whole microwave phase noise measurement system is about US$1000, an order of magnitude cheaper than anything else and within the budget of an amateur like me.

Regards Drew VK4ZXI

[hpw]

The local oscillator references I have are 10 MHz, just on what was available. The local oscillator signal generators are only about US$160. I am not aware of any other microwave signal generator that is locked to an OCXO at anywhere near the price.

The cost of the whole microwave phase noise measurement system is about US$1000, an order of magnitude cheaper than anything else and within the budget of an amateur like me.

As I wrote, I like to have a Turn Key solution (as finished with may different performance options) and NOT a DIY project more. As looks OXCO, mixer/splitter and any other parts to purchase.

This means, install the required SW & connect the HW and press the measurements at the SW. As getting what the seller promises. Nothing less or more.

Hp

[drew23]

Hi HP

The only phase noise analyser that is completely self-contained for GHz measurements is the R&S FSPN. They cost upwards of US$100k depending on top frequency.

Even the FSPN provides for external references and has low-noise power supplies for external amplifiers, depending on the measurement.

The other phase noise analysers are similar to the PN2060C, requiring external oscillators, mixers, amplifiers and power supplies. The other analysers are around US$10k, whereas the PN2060C is US$780.

Regards Drew VK4ZXI

https://qsl.net/bg6khc/pn2060c_phase_noise_analyzer.htm

[tautech]

Hi HP

The only phase noise analyser that is completely self-contained for GHz measurements is the R&S FSPN. They cost upwards of US$100k depending on top frequency.

SSA5000A models with PN option provide for this too starting under $20k.
https://int.siglent.com/products-overview/ssa5000a/
Latest App note:
https://int.siglent.com/resource-detail/65/

[switchabl]

That is a spectrum analyzer, it does not perform cross-correlation phase noise analysis. And it doesn't even have particularly low PN. The difference in sensitivity is on the order of 50 dB (!). I know many value the support you provide for Siglent products here. But I do wish that sales people everywhere would just learn to say "sorry, we don't have that" instead of automatically trying to sell you something that is obviously unsuitable.

The Keysight E505xA series is another turn-key microwave phase noise measurement system. It is also extremely expensive. The cheapest option would probably be the older E5052A. I'd expect a used 7 GHz model to be somewhere in the same ballpark as a new 53100A.

[3apw]

The only phase noise analyser that is completely self-contained for GHz measurements is the R&S FSPN.

•   AnaPico   
https://www.anapico.com/products/phase-noise-analyzers/apph-models-up-to-40-ghz/
APPH  - Fully Integrated Cross-Correlation Phase Noise Analyzer from 1 MHz to 7 / 26 / 40 GHz

•   Berkeley Nucleonics
https://www.berkeleynucleonics.com/phase-noise-testers
Model 7000 Series :  to 7 / 26 / 40 /50 /65 GHz  Phase Noise Tester - Signal Source Analyzer

•   Holzworth Instrumentation
https://holzworth.com/products/phase-noise-analyzers
HA7062 SERIES PHASE NOISE ANALYZERS : to 6 / 26 / 40 GHz

•   Keysight Technologies
N5511A : to 40 GHz
E505XA  : to 26 / 44 / 54 GHz

•   NoiseXT
https://noisext.com/solutions/phase-noise-analyzer/
PN9000 : to  1.8 / 6 / 40 / 140 GHz
NXA-6  : to  6 / 26 / 50 GHz
DCNTS  : to 50 GHz

•   Rohde&Schwarz   
https://www.rohde-schwarz.com/products/test-and-measurement/phase-noise-analyzers_254899.html
FSWP : to 8/26.5/50 GHz
FSPN :  to 8 / 26.5 GHz
FSUP :  to 8 / 26 / 50 GHz

[KE5FX]

Nice rock!  That's about the right noise floor for the 53100A, but I wonder where that artifact came from.  Normally you see that sort of thing if the DUT or one of the references is still warming up.  More typically you'd see something like this when measuring something below the unit's own spec floor:



(noise/spur responses near 1 Hz and 2 kHz are real)

[Gerhard_dk4xp]

https://synergymwave.com/articles/2013/04/full_article.pdf

[KE5FX]

The spurs shown at 4:30 do not originate in the PN test set, but are typical of the various CSAC models.  They aren't especially-well optimized for spectral purity, nor were they meant to be.  The major design goals for those parts are long-term stability and low power consumption.

E.g. if you do a Google image search for csac phase noise, you'll see a few references like this one that depict similar spurs with different instrumentation.  Unexpected spurious responses on the 53100A are often remedied by letting the measurement run a bit longer, but that's not an issue with the test shown in the video.

(Obligatory disclaimer: I work on the 53100A and related stuff, but I don't speak for Microchip.)

Edit: this was in response to a post that seems to have been deleted, which mentioned the spurious responses visible on a chip-scale atomic clock measurement in a 53100A demo video. 



Cool video, I hadn't seen it before.

[KE5FX]

No worries!

[sky2city]

From https://vk4zxi.blogspot.com/2024/02/pn2060a-ghz-phase-noise-measurement.html : "I don't know why AN3899 uses a single reference oscillator for the analyser as two would seem better for cross-correlation."

Since the downconverters are being used to measure a microwave source, the noise at each IF output is determined by the downconversion LO for that channel or the DUT, whichever is worse.  We can assume that the DUT will ultimately dominate, given that the LOs will tend to average out over time, and given that the microwave DUT is usually going to be much noisier than a decent 100 MHz reference OCXO. 

So when the IF is measured by the 53100A, the analyzer typically needs only a single reference OCXO, not a pair.

If you were using a pair of dividers, which allow the DUT noise to actually be improved by the downconversion setup, the story might be different.  E.g. in figure 5.  If dual references hadn't been used there, the measurement error at offsets >1 kHz would have been even higher.

Another question is raised in my mind,
I don't know why AN3899 didn’t uses image filter between DUT and mixer.
The white noise floor would be 3dB higher than the actual in this case.

[KE5FX]

Ideally, yes, you'd like some additional filtering, but it gets expensive to provide that in a multichannel test set with broadband coverage.  (Even the E5053A doesn't bother with that, which surprised me as well when I first noticed it.)  The use of image-reject mixers like the HMC8191 is the next best thing.

Also, this setup isn't intended for measurements near the kTB floor.  Besides the expense of maintaining low noise figures and high image rejection, there are other complications that arise when making cross-correlated measurements at lower noise levels.  The solutions in the app note are intended to be a good fit for the devices actually being measured in the app note.  For more demanding measurements, different approaches are called for. 

(Just to be clear, I'm the author of AN3899.)

[drew23]

Hi All

A dual-channel downconverter is available now from the bg6khc blog page. There are details of the down converters that are being updated day to day. The cost of two downconverter kits is US$558.

I have ordered them. A single unit would seem to be a cheap low-phase noise GHz signal generator.

I have both the PN2060A and Pn2060C. The PH2060C works very well with a noise floor below -180 dBc.

The PN2060C uses 125 Mbs ADCs so the Nyquist limit is 62.5 MHz. It is preferable to stay below this but the analyser works above this but with lower performance. See the blog page.

Regards Drew VK4ZXI

https://qsl.net/bg6khc/pn2060c_phase_noise_analyzer.htm

[testpoint1]

The only phase noise analyser that is completely self-contained for GHz measurements is the R&S FSPN.

•   AnaPico   
https://www.anapico.com/products/phase-noise-analyzers/apph-models-up-to-40-ghz/
APPH  - Fully Integrated Cross-Correlation Phase Noise Analyzer from 1 MHz to 7 / 26 / 40 GHz

•   Berkeley Nucleonics
https://www.berkeleynucleonics.com/phase-noise-testers
Model 7000 Series :  to 7 / 26 / 40 /50 /65 GHz  Phase Noise Tester - Signal Source Analyzer

•   Holzworth Instrumentation
https://holzworth.com/products/phase-noise-analyzers
HA7062 SERIES PHASE NOISE ANALYZERS : to 6 / 26 / 40 GHz

•   Keysight Technologies
N5511A : to 40 GHz
E505XA  : to 26 / 44 / 54 GHz

•   NoiseXT
https://noisext.com/solutions/phase-noise-analyzer/
PN9000 : to  1.8 / 6 / 40 / 140 GHz
NXA-6  : to  6 / 26 / 50 GHz
DCNTS  : to 50 GHz

•   Rohde&Schwarz   
https://www.rohde-schwarz.com/products/test-and-measurement/phase-noise-analyzers_254899.html
FSWP : to 8/26.5/50 GHz
FSPN :  to 8 / 26.5 GHz
FSUP :  to 8 / 26 / 50 GHz

Berkeley Nucleonics OEM ANApico

[pdenisowski]

•   Rohde&Schwarz   
https://www.rohde-schwarz.com/products/test-and-measurement/phase-noise-analyzers_254899.html
FSWP : to 8/26.5/50 GHz
FSPN :  to 8 / 26.5 GHz
FSUP :  to 8 / 26 / 50 GHz

The FSPN and FSWP are current products, but the FSUP has been discontinued for some time.  We also support phase noise measurements on our mid- to upper-tier spectrum analyzers (FXx-K40 option).  The FSPN and FSWP also support VCO testing.

I've done videos on all of these:
Analyzing Phase Noise with the FSWP

- Analyzing Phase Noise with the FSPN

- Characterizing VCOs with the FSWP:

- Characterizing VCOs with the FSPN:

- Analyzing Phase Noise with FSx-K40:



I also did both video and whitepaper introductions to phase noise measurements:

- Understanding Phase Noise Fundamentals:


- Understanding Phase Noise - the Spectrum Analyzer Method

- Understanding Phase Noise - the Cross Correlation Method

- Understanding Voltage Controlled Oscillators


The whitepaper versions are 90% the same material:

- Understanding Phase Noise Fundamentals: https://www.electronicdesign.com/resources/white-paper/whitepaper/55000557/understanding-phase-noise-fundamentals
- Understanding Phase Noise Measurement Techniques: https://www.rohde-schwarz.com/us/products/test-and-measurement/analyzers/signal-spectrum-analyzers/white-paper-understanding-phase-noise-measurement-techniques-register_255398.html

So if anyone has any questions about phase noise analyzers from Rohde & Schwarz, please let me know
[/list]

[testpoint1]

There is also a comparison among them .

https://kvg-gmbh.de/en/product/ocxo-beispiel/

the noise floor of 53100A is higher, can not compare with others, but I checked several test results of the PN2060 for OCXO testing, for the far end test result, the actual tolerance about 10dB, so, just for your reference, can not as a trustable test result.

according my latest testing (08/07/2024) for Datum 2750013-1, if low than -150dBc/Hz, test result is quite diff.

[tjadwy]

NIST's new work, 4 DDSs (9914) combined, very interesting.

https://tf.nist.gov/general/pdf/3257.pdf

[tjadwy]

So if anyone has any questions about phase noise analyzers from Rohde & Schwarz, please let me know

Thanks for sharing them, very intuitive.

4 ads5263 should be inside FSWP series PNA, a slimlar board is openly accessable on web. 

[zrq]

I have a question: is there any way of extending the measurement to beyond 50 GHz (say 58GHz) while taking advantage of the cross-correlation? Can we use external mixers and LOs for our FSWP (or something else)?