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True analog scopes
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tggzzz:

--- Quote from: 2N3055 on December 13, 2022, 03:48:30 pm ---There is only one thing where CRT is still better : X-Y mode for scope art..

--- End quote ---

Here's another: where a scope (analogue or digitising) with analogue sampling head is still the best: dealing with overload.

If you want to observe the full-scale transient settling time of an op-amp's or DAC's output to 0.1%, then an analogue sampling head is still required.

Any front-end analogue circuit will be overloaded and have "unhelpful" recovery from overload characteristics. In contrast, the analogue sampling head simply ignores any input (including overload) until the sampling instant. If I could get the thermal paper, I'd be able show a photograph of a chart recorder displaying 150ps risetimes :)

Of course, given an analogue sampling head, a pen chart recorder is sufficient for plotting the transient. No need for this fancy high speed display rubbish overkill.

I refer readers to the aphorism in my .sig.
TimFox:
As a practical matter in this modern age, there are no analog oscilloscopes in production that are as good as, say, a Tektronix 7904 or 2465.
I still use a 7603, but to operate a good Tektronix analog scope means having the dedication to maintain it yourself, just like owning a Saab.
2N3055:

--- Quote from: tggzzz on December 13, 2022, 04:16:49 pm ---
--- Quote from: 2N3055 on December 13, 2022, 03:48:30 pm ---There is only one thing where CRT is still better : X-Y mode for scope art..

--- End quote ---

Here's another: where a scope (analogue or digitising) with analogue sampling head is still the best: dealing with overload.

If you want to observe the full-scale transient settling time of an op-amp's or DAC's output to 0.1%, then an analogue sampling head is still required.

Any front-end analogue circuit will be overloaded and have "unhelpful" recovery from overload characteristics. In contrast, the analogue sampling head simply ignores any input (including overload) until the sampling instant. If I could get the thermal paper, I'd be able show a photograph of a chart recorder displaying 150ps risetimes :)

Of course, given an analogue sampling head, a pen chart recorder is sufficient for plotting the transient. No need for this fancy high speed display rubbish overkill.

I refer readers to the aphorism in my .sig.

--- End quote ---

What you say is absolutely correct. But.....

OP doesn't (and neither we are) talking about these types of scopes. They are very limited in usability and quite special.
These are not what people call analog CRT scopes. Such is popular lingo, sorry. Same as when people say digital sampling scope they mean Realtime DSO. Most never saw or used analog sampling scope and have no interest in it.

He specifically wants a comparison between classic analog CRT (direct writing of CRT with analog X/Y beam deflection) and modern real time DSO as a replacement.

We better not venture where more confusion will be brought in the picture..
tautech:

--- Quote from: precaud on December 13, 2022, 01:31:30 pm ---Besides familiarity and ease of use, there are two main reasons why I still keep a Tek analog scope on the bench:
7CT1N curve tracer plugin
7A22 diff amp

I'm still waiting for a DSO maker to offer anything remotely as useful as these two plugins.

--- End quote ---
It might not be long before Curve Tracers become another DSO feature but in the meantime while you're nursing that old gear along (no disrespect implied) you might like to look at what some have done in their spare time and follow a few links to observe where it led them:
https://www.eevblog.com/forum/testgear/fooln-around-with-dso-awg/

What's so special about the diff amp plugin that differential probes can't do ?  :-//
I'd really like to know.
tautech:

--- Quote from: vk6zgo on December 13, 2022, 02:39:09 pm ---I guess I will have to fix my Tek 7613!
--- End quote ---

--- Quote from: tautech on December 13, 2022, 09:16:18 am ---Just hope you don't need a working scope to do that !
--- End quote ---

--- Quote from: vk6zgo on December 13, 2022, 02:39:09 pm ---The (PSU) fault, luckily (in one way) doesn't need a decent 'scope to fix it---the little 10MHz Analog Digitech would do----it's just getting the motivation to do it.
The biggest problem is that everything else is jostling for position on the queue, & my "get up & go" has got up & went! ;D

--- End quote ---
:-DD Man do I know that problem too !
Shame we weren't visiting the lad this year as I'd happily bring some tools and help you fix it. Got aircon for them darn hot days you get this time of year ?
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