Re: test equipment

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Harvey,

The new "digital phosphor" scopes like the Tek 3000 series, and now
Agilent, show multiple trace paths in dimmer and dimmer colors on the scope
screen.  They try very hard to mimic the persistence of a analog scope and
they really do it very well.  Here is a nice sales blurb from Tek:

http://www.techni-tool-dot-com/CustImage/3GW_12482_5.pdf

Here are selected parts of it.  This shows how it handles multiple sweeps
like in your example.  It really looks better on the real scope:

http://hot-streamer-dot-com/temp/Image2.jpg

Of course, they are all computerized so they can do fancy stuff:

http://hot-streamer-dot-com/temp/Image3.jpg

Here it is picking out video lines for analysis,  Older scopes don't do
this stuff :-))

http://hot-streamer-dot-com/temp/Image1.jpg

Thus is why everyone is selling off their older scope dirt cheap to get
these new super powerful ones...

A long standing complaint of digital scopes was that they only show a
single trace path and loose the previous trace information unlike analog
display tube scopes.  Thus, Tektronix went to a lot of trouble to add
analog scope like persistence to digital scopes using a ton of digital
processing.  This allows a lightweight computerized digital scope to have
persistence in the screen.  Of course, once designed, a speck of silicon is
a whole lot cheaper than a precision vacuum tube.  It really works very
well.  Unfortunately, the digital scopes you find on E-bay are all the
older ones that show just a single line.  The newer scopes like the 3000
series are almost impossible to find used.  I saw one slightly used one go
on E-Bay for more than the brand new price =:O

Cheers,

	Terry


At 10:31 PM 3/12/2002 -0800, you wrote:
>
>--- Tesla list <tesla-at-pupman-dot-com> wrote:
>> Original poster: "Allanh by way of Terry Fritz
>> <twftesla-at-qwest-dot-net>" <allanh-at-starband-dot-net>
>> 
>> I've been using O'scopes for 40 years and have
>> bought a
>> few used ones. I've come to the conclusion that
>> expensive
>> ones like Tektronix, HP etc. are to be avoided. I
>> also do
>> not recommend any digital scopes as they have not
>> reached the point of being
>> able to replace analog scopes in all applications. I
>> worked as the mastering
>> engineer at a
>> CD plant for over 13 years. Every month or so Tek
>> and HP salesmen would
>> offer to leave me their "newest" models so that I
>> could tell them what was
>> wrong with their
>> algorithms.  I almost never took them up. I showed
>> them that their 20K$ plus
>> machines could not match a
>> $400 analog when it comes to real world information
>> about freq. below 20 Mcps. especially when viewing
>> complex bursts of mulitfreq. energy.
>I always wondered how a digital scope would record a
>phenomenon of exessive rf bursts per time period. In
>the beginning of work with rf from huge inductors this
>multitracing phenomenon was very common. With every
>"ordinary" scope I have tried one gets a phenomenon of
>multitracing as shown at 
>http://groups.yahoo-dot-com/group/teslafy/files/BRMA/Dzl9356.jpg
>  This was made at 5 us/div from a very low ~31,250
>hz, from  bifilar inductor subjected to impossibly
>high BPS rates, made via small bulb neon polar
>discharge. How would a digital scope deal with that?
>HDN