7B85: Difference between revisions

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{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Sweep | 5 s/Div to 10 ns/Div in 1-2-5 sequence, ×10 magnifier down to 1 ns/Div, variable to ×2.5}}
{{Spec | Sweep | 5 s/div to 10 ns/iv in 1−2−5 sequence, ×10 magnifier down to 1 ns/div, variable to ×2.5}}
{{Spec |Triggering | to 400 MHz }}
{{Spec |Triggering | to 400 MHz }}
{{Spec | Features |  
{{Spec | Features |  
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==Links==
==Links==
* [[Patent US 4109182A]]
* [[Patent US 4109182A]], ''Delayed sweep system for an oscilloscope''.
* [https://m.youtube.com/watch?v=Hz-gF_XSj9w Demonstration of delay and delta time measurement on a 7B85]
* [https://m.youtube.com/watch?v=Hz-gF_XSj9w Demonstration of delay and delta time measurement on a 7B85]
{{Documents|Link=7B85}}
{{Documents|Link=7B85}}


==Internals==
==Internals==
The 7B85 uses a [[155-0185-00]] digital voltmeter IC (U686). A ramp generator is started when the trigger signal arrives.
The 7B85 uses a [[155-0185-00]] digital voltmeter IC (U686).  
A ramp generator is started when the trigger signal arrives.
The delayed sweep is started when a comparator detects that the ramp has reached a control voltage, set by the front panel knobs on the 7B85.
The delayed sweep is started when a comparator detects that the ramp has reached a control voltage, set by the front panel knobs on the 7B85.
The control voltage is proportional to the amount of delay.
The control voltage is proportional to the amount of delay.


The digital voltmeter in the 7B85 digitizes the control voltage and displays it on the [[7000 series readout system|oscilloscope readout]],  
The digital voltmeter in the 7B85 digitizes the control voltage and displays it on the [[7000 series readout system|oscilloscope readout]], thereby providing the operator with a precise readout of the delay.
thereby providing the operator with a precise readout of the delay.


Another way of setting up a precisely delayed timebase is to use a [[7D11]] digital delay module.
Another way of setting up a precisely delayed timebase is to use a [[7D11]] digital delay module.