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QUOTE:? Phase noise and jitter are valid issues, so maybe this is too.

I've measured many......many...... canned PLLs and clock oscillators with atrocious noise pedestals!? Phase noise, amplitude noise, and jitter are all real issues with many of these PLLs.?

I once was called in to trouble-shot a highly distributed storage system which could not perform properly due to "jitter" (phase incoherency).? I won't go into the whole story, but ultimately, a "cheap" PLL in the low 100's of MHz had been chosen to be used in the entire distributed system.? It was chosen for only two criteria:? frequency and price.? When I went in to isolate the cause of the system wide jitter, this cheap PLL measured ONLY -10 dBc to the noise pedestal.? Further, the noise pedestal measured some 5 MHz wide!? No wonder the system didn't operate as expected.?

Further, few of the newbies, be they EEs or CS degreed at the BS or MS levels, have any inkling of the contributions and importance of these parameters in specifying PLLs.

Recently, R&S has published an excellent online tutorial addressing these parameters, but few newbies will read it as it was addressed to a very select readership.? I've seen it twice in the last 6 months, but it was addressing us EMC/RFI engineers.??

Dave - W?LEV? ?