On Sun, 21 Apr 2019 05:33:05 -0700, you wrote:
On Wed, Apr 17, 2019 at 07:55 AM, Harvey White wrote:
On Wed, 17 Apr 2019 07:06:19 -0700, you wrote:
I have been given this tool. I have a Tek 2246A and a Hitachi scope already.
What can I do with this that I can't with the other scopes? I have never done
anything with video nor intend to. Also, the trace is hiding deep lower left
of CRT. Can't get it out of there.
If you're doing anything with baseband video, such as CCTV cameras for
surveillance systems, video tape recorders, etc., then you'll want
this.
It looks at very specific things on the video waveform with an ease
that is hard to duplicate on most oscilloscopes unless they have some
very specific TV signal processing/filters built in.
Having said that, this is the old standard 450 or so line resolution,
analog video, 75 ohms, 1.4 v p-p video that uses either BNC, SO-239,
or RCA jacks (on consumer equipment).
Generally not found as much as you'd think.
If you never intend to do anything with video, then it won't be of
much use to you. As has been mentioned, it's not a general purpose
scope.
Harvey
Both my existing scopes have a TV trigger setting. Since this is a specialized tool, I get the idea that a general use scope won't be likely to duplicate what it can do.
I might do some security camera surveillance in the future with my business. What value would this have for that? Would my existing scopes fill that need? I am determining if I should offer this for free to the group.
There's a difference here.
The TV sync settings on a "normal" scope allow jitter free (or at
least easier) triggering on a TV waveform.
To set up a video system, there are often VITS (Vertical Interval Test
Signals), which you could sometimes see by rolling the picture down or
underscanning it on one of the old broadcast TV signals.
Literally, you'd want to look at line N out of 525 to find the signal.
There were also standards for the height of the vertical/horizontal
blanking, sync, color burst, and so on. The video monitor had
controls, trigger circuits and logic inside to make that kind of
waveform observation easy.
For instance, on a conventional scope, looking at line N involves two
time bases and a digital delay counting horizontal sync pulses. The
waveform monitor has this as a switch setting.
Most of your existing scopes would do reasonably well in diagnosing
CCTV stuff, because you're not messing with the things that this
waveform monitor is designed to do. In the earlier days of TV, all
these parameters were adjustments and set up by the chief engineer
during maintenance.
With today's CCTV stuff, all of this is pretty much fixed in chip
design, not made to be adjustable, and you're more looking for absence
of signal or gross distortions than not.
*I* would keep it (and I have a similar Hitachi monitor and a vector
scope), but just because I know where a few bodies are buried.
However, if you ever maintain, want to maintain, or think you might
ever work on VHS or Betamax, any of the older video technology up to
but not including DVDs (although the composite output may be
interesting), then I'd definitely keep it.
Harvey
NielsenTelecom
