Hi Karl, not sure if I can help much more here, one things that might be useful is measure the Allen variance? Perhaps someone at NIST or NPL in the UK might have methods to characterise the phase noise of your sources. Good luck. Neil
-----Original Message----- From: casper@lists.berkeley.edu <casper@lists.berkeley.edu> On Behalf Of Karl Warnick Sent: 20 August 2024 22:01 To: salmon.na via casper@lists.berkeley.edu <casper@lists.berkeley.edu> Subject: Re: [casper] Low cost phase noise analysis Hi Neil, thanks for responding. I'm working at 25 MHz. I have five different clocks ranging from from low cost clock chips to expensive stable sources. The project started with looking for an easy benchtop way to compare their stability without an expensive analyzer. More specifically, when we realized that the mid range spectrum analyzers of which we have several couldn't measure phase noise low enough to distinguish any of the clocks. It's not an issue of finding good clocks as we have that but comparing stability among them. Best, Karl On 8/20/2024 2:48 PM, salmon.na via casper@lists.berkeley.edu wrote: > Hi Karl, > > Cant you just use specifications on phase stability of standard sources of > varying degrees of stability which would be a function of price? What radio > frequency are you working at. Tube sources tend to have good phase stability. > There might be some old but goodies on ebay. There's also an HP user group > https://groups.io/g/HP-Agilent-Keysight-equipment where you might find a few > low cost sources from those I keep the old kit working. Also a good source of > technical data on radar technology and knowhow. > > Cheers, > Neil > > -----Original Message----- > From: casper@lists.berkeley.edu <casper@lists.berkeley.edu> On Behalf > Of Karl Warnick > Sent: 20 August 2024 21:38 > To: casper@lists.berkeley.edu > Subject: [casper] Low cost phase noise analysis > > Hi all, > > I've spent some time this summer as part of a radar project digging into > calculating phase noise for highly stable tones. I have implemented what I > think is a decent algorithm. My next steps are to look for test data sets and > tips for the hardware. > > Do you have a file of samples of a stable tone? If anyone has a test data set > consisting of samples of a pure tone that they would like to share as a test > data set, I'd like to apply my codes to that and check the phase noise. Both > the tone generator and the ADC sample clock should be phase stable to the > order of a Keysight signal generator, or ideally better. The data set length > should be a reasonable fraction of a second for ~1 Hz phase noise resolution. > The frequency of the tone and the sample rate are fairly arbitrary as I'm > mainly looking to benchmark the algorithm. > > How cheaply can stable samples be acquired? I'm looking for low cost hardware > (a few $100s up to a few $k) that is stable enough to measure phase noise > comparable to a Keysight source or better. Phase noise can be measured with > an expensive phase noise analyzer, but I believe it should be possible to do > this with a low cost digitizer with a suitably stable sample clock. The > sample clock could (or perhaps must) be external. The sample rate should be > around 80-100 Msps or higher and the platform should be able to store a burst > of samples of length on the order of 1 sec. We have done this using a ZCU 216 > and it seems to work, but that isn't really a low cost board. I've looked > into Picoscope products, which might be ideal, but their support people don't > know anything about the phase noise properties of their samplers. > > Thanks in advance to anyone whose interest is piqued enough to respond. > > Best, > Karl > > -- > Karl F. Warnick > Parkinson Engineering Research Professor Department of Electrical and > Computer Engineering Brigham Young University > 450 Engineering Building > Provo, UT 84602 > (801) 422-1732 > > > > > -- Karl F. Warnick Parkinson Engineering Research Professor Department of Electrical and Computer Engineering Brigham Young University 450 Engineering Building Provo, UT 84602 (801) 422-1732 -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/f1b82739-9bd9-4e76-8f6c-a797c31b94a0%40ee.byu.edu. -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/00a501daf345%2416a97bf0%2443fc73d0%24%40tiscali.co.uk.
