HP 53310a Modulation Domain Analyzer

[ruairi]

Hi all,

I've been using a friends HP 53310a to look at some clocks in an AP system one as well as word clocks in my studio.  It's a truly wonderful machine and a joy to use.

I've considered picking one up as they are fairly affordable.  Option 10 adds an Oven Controlled Crystal which improves performance and there are used units available with that option.  The other approach of course is to connect an external 10 MHz reference.

For someone who is interested in looking at clocks mainly for audio in the MHz range is there a sense of which might perform better/be more appropriate?  I must admit to knowing very little about 10MHz references, GPS locked or otherwise.  Are they better for long term accuracy or short term stability (the latter is more important for my purposes).

Excuse my ignorance, this is a new area of study for me.

Thanks,
Ruairi

[bingo600]

For short term stability , not much is better than a good well aged OCXO.

/Bingo

[wn1fju]

You can start a lot of arguments on the subject!  I suggest you google "Time Nuts" and look through some of the contributor's pages.  In my experience, the "experts" seem to care mostly about stability, not accuracy, for their argument is that they can calibrate out the inaccuracy (once they measure it).  A good OCXO usually has nice short term stability, but the Allan Variance (a measure of stability) tends to climb back up at longer time intervals.  The GPS disciplined OCXO tends to force the Allan Variance back down.

I also have an HP 53310A and consider it one of HP's most "under-advertised" pieces.  I also have its cousin, the HP 5371A, which can do a few more things, but runs a lot slower than the 53310A. 

A bit of caution on a used one, however.  The Boeschert power supplies are notorious for leaking their electrolytic caps.  I've had the occasion to work on two 53310As, and both supplies were toast.  Fortunately, they also can be found in a lot of other HP pieces, like some of their scopes and logic analyzers.

[ruairi]

Superb info Gents, thank you.

[G0HZU]

I can remember using the HP53310A back in the 1990s as a tool for measuring/plotting synthesiser lock time. Prior to this I had tried various classic methods for testing lock time on my designs but the HP53310A was a huge step up in performance both in terms of speed, accuracy and also in the level of detail seen during the lock process. A classic piece of HP test gear