[time-nuts] Very stable synthesizer, alternative to PTS(Programmed Test Sources) x10 or 040?
stefan_heinzmann at gmx.de
Thu Jul 11 03:45:37 EDT 2013
Jim Lux wrote:
> On 7/10/13 12:29 PM, Didier Juges wrote:
>> Jim said:
>> "It's like a HP 8663B (not the modern Agilent E8663).. very low noise,"
>> The Agilent E8663 has similar SSB phase noise spec as the older HP 8662A
>> (-144dBc/Hz @ 10 kHz with option UNY, versus -143 for the 8662). You
>> to imply they are different. Can you elaborate?
>> Of course, the Agilent has many more features and 0.001Hz resolution,
>> the 8662 only goes to 990MHz (I think, I should know, I have two
>> thanks to
>> JohnM...), but are they that much different in pure phase noise or ADEV?
> It's not the phase noise that raised the problems for us. It's that
> when you program them for a sweep, it goes in steps that aren't phase
> continuous AND the behavior when you feed a signal into the FM input
> isn't the same. The HP 8663B was, at the core, a really good phase
> locked VCO, so when a sweep is programmed, the output is phase
> continuous as it sweeps. This is a huge problem when you are testing
> a very narrow band tracking loop (our deep space transponders have a
> loop bandwidth of a few Hz)
> I can't remember the details on the FM input, but it too has some
> behavior that we depended on.
> We take the output of the 8663B and run it into a x7 to make the 7150
> MHz uplink and/or the 8450 MHz downlink frequencies.
> Part of the reason we do a x7 is so that any leakage from the
> synthesizer isn't in band for our receiver under test. A typical input
> level for test is -150 to -160 dBm, so leakage at the wrong frequency
> can easily be more than the desired signal.
Now you're confusing me. As far as I am aware, there was the 8663A which
appeared in the early eighties. And much later came the E8663B, and
subsequently the E8663D. I've never seen an 8663B from HP. From the
context I would guess that you really mean the 8663A, and not the 8663B,
More information about the time-nuts