On Thu, 4 Oct 2018, panpupez wrote:
On Thu, Oct 4, 2018 at 05:47 AM, Sergey Kubushyn wrote:
9374L. I've been thinking of buying LC684DXL but it is not a very big
improvement for occasional use. I don't like DSOs and prefer my trusty
beloved 2467B unless I absolutely need some DSO-specific feature. It doesn't
happen often and for logic level signals I have HP 16702B with 10+ different
plugins that beats any DSO by light years in digital domain.
And I don't wanna use those Windoze-driven "instruments" at all.
What do you like most in you 2468B (vs 9374L)?
Immediate response, no dead time, very easy and intuitive to operate,
immediate visibility of various rant pulses and irregularities (i.e. you can
easily spot parasitic oscillation at pulse edges and elsewhere with
amplitudes much smaller than main signal itself and frequencies several
orders of magnitude higher than the main signal), no aliasing so what you
see is actually what's in there, no need to fight with the part of signal of
interest to fill the entire screen to get even 256-levels (8-bit) resolution
so you can actually see something and simultaneously somehow making sure no
part of the signal overloads the ADC and much more...
They say newest DPO scopes are almost as good as analog ones but they are
"almost" as good actually being nowhere near yet, prices are astronomical,
they run Windoze and you have to pay extra for every sneeze beyond not very
useful basic functionality. Then comes the very nature of the beast --
limited resolution so you can only see an approximation of whatever is there
and you can NOT e.g. tell the thing oscillating by noticing the trace
getting slightly "fatter", with that resolution decreasing if your signal
does not take entire screen and everything screwed if it exceeds that,
horrible deadtime, low repetition rate (you only have your screen updated 60
times per second at most), lack of analog persistence and much much more.
Sure, there are SOME applications where they really shine and irreplaceable
but many of those areas are covered with other, specialized instruments that
are better for particular jobs (SA, VNA, LA, Modulation Analyzers, etc) and
remaining few applications are specific for some particular jobs that are
only relevant if one works in some special field. They are also good for
documenting something because you don't have to take screenshots with a
camera but other than that they have a long road ahead of them to get as
good as old analog scopes.
There is also another jewel I keep and admire -- 7834. It is big, ugly,
requires significant effort to refurbish to like new condition but it has a
huge assortment of different plugins that allow doing things not even
dreamed of on most expensive DSOs and REAL analog variable persistence is
light years ahead of DPO or whatever other simulation available in DSOs
these days. It is real-time, incredible simple with just one stupid analog
potentiometer control -- pure pleasure to work with...
I am interesting because i use (and have) many analog and digital
oscilloscopes, and 9354L was the fist DSO i liked, mostly because great
functionality(mathematics), i can see signal buried in noise using
averaging, FFT, inboard CAL out+mathematics = frequency response
measurement, statistical measurement etc. Thats why i sold my 2465A at
that time. But 9354 have no analog persistence, not great sampling rate
and very big dead time compared to analog Tektronix. Now I use as main
scope LC684DXL, and it is a big step up comparing to 93xx series, but dead
time almost the same. And now i have not only on work, but also in home
lab NA and SA and don't need most of 684DXL features. I was thinking to
bye 2467B :) but i don't know why do i need it, maybe nostalgie..
---
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Sergey Kubushyn