"k4kqz" ha scritto nel messaggio ...


How do you define "poor" stability? Scott is exactly right- units as the
3312 were not necessarily intended for long term stability. His
suggestion of letting the unit warm up then checking is very good
advice. Most test equipment is speced based upon a warm up period of
usually 30 minutes. I had a couple of 3312s over 25 years ago in my
design lab and they were fine for lots of the work we were doing. If you
have a unit that is truly drifting badly over a short period of time
after warm up then I'd say it has a problem. However, I don't know if
you'll find a drift spec for that particular unit. Best I recall we
(yes, I worked for HP/Agilent) didn't routinely spec drift on the low
cost units until DDS came about. But one thing is sure- we were pretty
much always better than anyone else with respect to most any
specification you picked! Output jitter was especially bad on some
competing units.

John

John, I here report the answer I gave Scott.

Unfortunately the HP manual does not tell the frequency stability. No useful
information found searching the web.

Frequency measurement results:

- Just turned on. Frequency = 5.000 MHz Delta F = 0
- 15 minutes after. Delta F = -98 kHz
- 30 minutes after. Delta F = - 116 kHz
- 45 minutes after. Delta F = -132 kHz
- 60 minutes after. Delta F = -141 kHz
- 75 minutes after. Delta F = -147 kHz

Again the question is: is my generator faulty or all instruments based on
the same (analog) frequency generation principle (charging a capacitor at
constant current) behave more or less the same?

73

Tony I0JX