Fluke Scopemeter Glitch Detection and Noise

[Neik]

I recently had the chance to play with a couple of Fluke Scopemeters:
the 123 and the 199C. They both seem much noiser than a standard
analog scope. There is some kind of Glitch Detection "feature" where
the scope highlights any high frequency (around 40ns on the 123) noise
in the signal. You can turn this off on the 199, but not the 123. Even
then the trace is still rather noisy.

If you pull the waves off the scope using the Flukeview software you
can see that a nice 1kHz sinewave is very uneven, especially at the
peaks.

Looking at a video signal on the 199 the color burst was just a solid
blob with glitch detection on, but was much more visible with it off.

Can anyone explain what is going on? Are Fluke trying to make a virtue
out of some underlying problem with these scopes?

 

[Jean-Yves]

In article <1187646507.579554.129870@r34g2000hsd.googlegroups.com>,
Neik <neik@mailshack.com> wrote:

I recently had the chance to play with a couple of Fluke Scopemeters:
the 123 and the 199C. They both seem much noiser than a standard
analog scope. There is some kind of Glitch Detection "feature" where
the scope highlights any high frequency (around 40ns on the 123) noise
in the signal. You can turn this off on the 199, but not the 123. Even
then the trace is still rather noisy.

If you pull the waves off the scope using the Flukeview software you
can see that a nice 1kHz sinewave is very uneven, especially at the
peaks.

Looking at a video signal on the 199 the color burst was just a solid
blob with glitch detection on, but was much more visible with it off.

Can anyone explain what is going on? Are Fluke trying to make a virtue
out of some underlying problem with these scopes?

you pointed out the main problem on digital scopes versus analog ones...
for some signals (for example video) an analog scope is still better...
except the fact that these fluke scopes are really portable...

fluke used to design combiscope (digital+analog in the same scope) but
they dont build them anymore. hameg has still such scopes
you can memorize (long) waveforms with the digital part, and still have
good video signals with the analog part.
but they are also not portable...

everything depends on what you have to do with the scope.

--
Jean-Yves.