[time-nuts] HP 5335A Option 040

[Dr. Frank Stellmach]

Hi,

there exist three manuals,
5335-90005 - Serial #2024A and below, 1980, preliminary pdf manual on 
agilent.com
5335-90021 - Serial #2224A and below, 1983, pdf from Artekmedia, very 
good scan for $7.50
5335-90044 - Serial #3154A and below, 1994, very good reprint from 
manualsplus for about 70$

If you don't have the latest device, Artek Media document is absolutely 
sufficient for description of Opt. 040, i.e. HPIB instruction set and 
schematics. (SW is different, also input amplifier / front end   A12  
and amplifier support A11)


Btw.: I've got a nice 5335A with ser no 2820, Opt. 10, 30 , 40 (10811 
oven, 1,3Ghz C-input - latest divide-by-64 version, and full front end 
remote steering).

I've found out, that it definitely resolves 1ns in Time and Freq. 
measurements, in contrast to 2ns as stated by all the latest specs. in 
the manuals and all the HP catalogues.

Gordon, and other 5335 owners - would you please check your instruments 
on that, to find out if firmware has changed later on, or simply if the 
specification is wrong?


I get 11 significant digits over the bus and on the display, if I 
measure for >100s.
I'd expect 12 digits for >1000s at least over the bus, as 14 digits are 
reserved for the mantissa (incl. sign and decimal point) but nothing 
happens.

Anybody got an idea, how to get more digits, perhaps with undocumented 
commands?
This counter potentially delivers nearly unlimited resolution, as the 
overflow is counted in many additional bytes, which I would like to read 
out.


Thanks - Frank