[time-nuts] Re: HP 8663A: option 003

[John Miles]

> Which brings me to the question of the interfaces (I have none of
> them, but do have two 8662s and would be interested in making some PN
> measurements). The 3047 used the spectrum analyser interface 35601A
> which I know almost nothing about and the 3048 used the 11848A for
> baseband or 11729B/C for mixed down measurements. Are they all equally
> useful today, possibly with a more modern FFT analyser as some of
> those HP dynamic signal analysers have very low numbers of bits in the
> ADC even compared to a soundcard!

Given that a 3048A system isn't too expensive to put together, it's probably
not worthwhile to assemble a 3047A system today unless you already have a
35601A and 3582A ready to go.

Unfortunately the various FFT analyzers made by HP are completely
incompatible with each other due to different GPIB command sets.  Only the
3582A can be used with the 3047A software, and only the 3561A can be used
with the 3048A.

Bit depth is not a concern for two reasons, one being that the interface
boxes have a number of variable gain stages to make the most of the
available dynamic range, and the other being that you're going to be
measuring at 1 Hz resolution anyway, so the effective bit depth is higher
than what the hardware ADC provides.

-- john