The Origins of Delayed Timings on Oscilloscopes - Workbench Wednesdays
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- Опубліковано 22 лип 2024
- Almost everyone uses a digital oscilloscope’s zoom features. However, did you know that 40-year-old analog oscilloscopes can do something similar? Delayed time bases on analog scopes sweep twice so that the user can see a slow and fast sweep. In this video, see where “zoom” came from and how engineers accomplished the same measurement back in the day: bit.ly/3mODDj6
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The Tek 7834 was a storage version of your 7704. It used a special storage CRT that could capture single sweeps and hold them on screen for analysis.
Back in the day they really put time and effort into designing hardware for ease of access and serviceability. I can't bring myself to toss out my old gear for that reason. Great video and nice scope!
Delayed timebases were first introduced in 1954 on the Tektronix 535. Long time ago!
fantastic walk through, and a beautiful old scope!
If demonstrated with a dual timebase like the 7B92A the zoom feature is even more intuitive.
Learned analog Tektronix oscilloscopes before using digital ones for work and I am sometimes frustrated how hard it is to set up certain signals with some digital scopes that were knobs are minimalistic and menus are deep
If only my analog scope did not have a broken B/DlY'D/Trigger knob...then I might actually be able to use this feature 🤔 Awesome video as always!
My 7834 does 400MHz single shot that stays around for viewing if you want.. its a storage scope. My 7104 does 1 GHz and with microchannel image intensification also allows viewing of single shot events..
My R7844 is a 400MHz true dual beam. All these easily do things my 200MHz, 2GS DSO can't even dream of.
I need to crack open my analog scope... Maybe it also just has a bad resistor keeping it from working....
You can also get a 7B92A and get that in one time base. You should search for a 7854 which will get you very close to a modern digital scope. The extra keyboard is not really needed esp if you use GPIB.
excellent
Gorgeous 7704...
great job guys
is delayed timebase the same thing as trigger holdoff?
Short answer, No. Longer, full answer here: www.element14.com/community/docs/DOC-96903/l/workbench-wednesdays-43-the-origins-of-delayed-timings-on-oscilloscopes#comment-284505
Since the 1960s! :-)
The other interesting thing is that the glitch as displayed on the analog scope had nice square edges. Now, as frequency goes up and pushes the rise time capacity of the scope, you will lose the sharply defined corners. BUT the digital scope had a squiggly shaped waveform, nothing like a square shaped pulse.
Didn't some modular Tektronix boob tube scopes have a memory feature?
Sure, both modular and non-portable models. A few examples: 7613, 7623, 7633, 7834, 7934, 464, 466. These all have storage ("memory") on the CRT screen itself. Some had pretty fast single-shot storage. The 7854 analog 'scope had digital memory and could even be programmed with its own separate keyboard. A plugin (7D20) existed for the modular 'scopes, making the analog 'scope a digital one by using the 'scope as a monitor for a complete digital acquisition unit (70 MHz BW). In the low-cost 5000-series plugin 'scopes, analog and digital storage modules existed as well.
Boob tube scopes...the 500 series, yes. The first one that had delayed timebase was the 535 introduced in 1954. There was also a storage scope - the 549 - also a tube scope from (I think) the 50's although maybe early 60's. The 564 was also a storage scope that was introduced in around the early 60's.