Re: Advise needed - thinning the herd

Gary Robert Bosworth
 

Keep one 7854 and one 7904.


On Thu, Nov 3, 2016 at 7:30 PM, David @DWH [TekScopes] <
TekScopes@...> wrote:



On 03 Nov 2016 09:23:36 -0700, you wrote:

That is in fast transfer mode which is considerably annoying to use
and really only suitable for single shot applications where it is
admitted invaluable. Even then it is only 5500 div/us for the 7834
and 8800 div/us for the 7934 in reduced scan mode.
"Only 5500 div/us" allows me to see a single shot 1 ns edge across some 2
cm as per spec. In practice I can see the full edge of my 700 ps PG506
across some 4 full divisions (Fast Variable Persistence at Reduced Scan, or
Fast Transfer Mode). It shows as about 1.1 nsec. Admittedly, these are very
specific cases but I wouldn't call this mode particularly annoying to use,
especially on a 7834 or (slower) on a 466.
To see that on a DSO, you'll need something like a 5 GSa/sec sample rate.

Of course, you'd want some form of variable persistence in many cases. In
that mode, Full Scan Fast Variable Persistence is still spec'ed at 300
div/usec or 270 cm/usec for the 7834.
In many instances, standard Variable Versistence will do, even at only 2
div/usec, like in the examples (images) you linked to.

I can't help being a fan of analog storage for many applications, witness
my 464, 466, 7613, 7623A, 7633, 7834, all in good shape.

I find that the limited possibilities but fast reaction and storage speed
of a faster analog storage 'scope still have great appeal. And at the
prices they achieved a while ago, why limit myself to the least performing
7613?
My 7L13 permanently lives in a 7613...

Raymond
Oh, the fast capture modes definitely work and I bought a 7834 for the
same reason; it was the least expensive way to get 400 MHz single shot
capture performance. For repetitive applications however, variable
persistence mode is much easier to use.

Getting back to the original topic, if I was limited to one 7000
mainframe, then it would be one of the variable persistence models. If
I was limited to two 7000 mainframes, then one of them would be a
variable persistence model. But the fast transfer modes would not be
a consideration.



--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247


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