[time-nuts] Selecting a used HP sweep/frequency generator
Charles P. Steinmetz
charles_steinmetz at lavabit.com
Fri Apr 15 18:57:39 UTC 2011
Jim wrote:
>Some oddities [of 3325A and 3325B's]:
>you can't get non-sine at as high a frequency on the front panel. I
>think square waves go up to 10 MHz or so..
>The backpanel waveform is always a sine, but not necessarily a very
>high quality one.
The triangle and ramp signals only go up to 11 kHz.
The logarithmic sweep on a 3225A or B is accomplished by piecewise
linear approximation -- 10 segments/decade in single-sweep mode, and
only 2 segments per decade in continuous mode -- so its utility as a
continuous, wide-range logarithmic sweep generator (for example, as
one would generally want for audio testing) is limited. The markers
do not work in log sweep mode, either.
As a radio generator, not so bad. But be aware that 1 mV p-p (~ -56
dBm) is the minimum output, so you need good external attenuators for
it to be fully useful in that role.
The 3324A is, in my view, the sleeper of the bunch. First, it powers
up the way you left it rather than set to the factory defaults
(unless you set it to emulate a 3225). Second, IME the output
attenuator assembly is more reliable than either the 3325A or B. And
finally, they are usually much cheaper. Of course, if you need
frequencies down to uHz rather than just mHz, you need a 3325.
Best regards,
Charles
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