Hello Javier, Wavecrest makes a point of saying they do not operate like a sampling scope, rather like a Time Intervall Analyzer with very high resolution, and up to 40.000 measurements/s. See for example page 12 in the manual at this location: _http://www.mhzelectronics.com/ebay/manuals/wavecrest_dts-2079-77-75_digital_time_system_manual.pdf_ (http://www.mhzelectronics.com/ebay/manuals/wavecrest_dts-2079-77-75_digital_time_system_manual.pdf) A sampling scope has all sorts of aliasing issues, and typically much lower resolution and noise floor, and is not very good at single-shot events. Their Visi software does have an Oscilloscope view as well btw. The Wavecrest website is gone, maybe they are bankrupt? I have most of their manuals and appnotes in PDF form if you need them. They do a time intervall measurement using counters running at 100MHz and analog interpolators, similar to an HP5334A etc. They took this to another dimension though with 800ps resolution at 40000 samples per second and gated arming capability etc, up to several GHz bandwidths. The Visi Windows software has special routines for PLL measurement etc., and this also includes TIA-to-Phase Noise graphing, although I do not find that feature very useful. What is extremely useful in your application is the Jitter histogram (you can see and quantify immediately if jitter is deterministic, and/or random, and what the side lobes values are etc). See the attached example plot, you can see the jitter being split into left, right, random, total, deterministic jitter etc etc. (That happens to be a very low noise OCXO) Since they are concerned about edge-to-edge jitter, it is best to have nice fast rising/falling edges on your signal. While Sine Wave signals do work, the unit will give you a lower phase noise floor if you buffer these from Sine Waves to say LVDS signals, or CMOS signals. They are somewhat rare to find, and some distributors try to get $30K or more for them, but I have been able to buy several for around $500 on Ebay in the past. bye, Said In a message dated 10/13/2008 14:06:09 Pacific Daylight Time, javier.serrano.pareja@gmail.com writes: Said, what is the operating principle of the Wavecrest Jitter Analyzer? Is it a sampling scope like the ones Agilent and Tektronix offer? How does it compare to them? I've googled it but I only found a Chinese site with little information in English. Another advantage I see for time-based measurements is that you can go arbitrarily low in offset from the carrier. In the 5052B you have a PLL with non-zero bandwidth, so below some offset you probably get an optimistic estimate because the PLL is actually following the noise. Another item to bear in mind, if my understanding is right, is that integrating the phase noise plot gives you the rms jitter between your noisy waveform and the perfect sinewave, or rather an approximation of it, which is what comes out of the PLL in say the 5052B. A sampling scope typically measures the time jitter between two (noisy) rising edges of a clock waveform. In the simplistic case of white phase noise this should give you a factor sqrt(2) more jitter than the loose PLL measurement, right? Thanks again, Javier **************New MapQuest Local shows what's happening at your destination. Dining, Movies, Events, News & more. Try it out! (http://local.mapquest.com/?ncid=emlcntnew00000001)