7B85: Difference between revisions
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{{Plugin Sidebar| | {{Plugin Sidebar 2| | ||
title=Tektronix 7B85| | title=Tektronix 7B85| | ||
summary=400 MHz Delaying Timebase| | summary=400 MHz Delaying Timebase| | ||
image=Tek 7b85 front.jpg | | image=Tek 7b85 front.jpg | | ||
caption=Tektronix 7B85 Delaying Timebase plug-in| | caption=Tektronix 7B85 Delaying Timebase plug-in| | ||
introduced=1976 | | |||
discontinued=(?) | | |||
series=[[7000-series scopes]]| | series=[[7000-series scopes]]| | ||
manuals= | manuals= | ||
Revision as of 09:44, 21 August 2014
The Tektronix 7B85 is a 400 MHz delaying timebase for 7000-series scopes, typically the 7800 Series, e.g. 7844. The trigger circuit is similar to that of the 7B80. The digital delay differentiates the 7B85 from the 7B80. The 7B87 is similar to the 7B85 but provides an acquisition clock for a digital storage mainframe instead of a delay.
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 control voltage is proportional to the amount of delay.
The digital voltmeter in the 7B85 digitizes the control voltage and displays it on the oscilloscope readout, 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, or even a time mark generator such as the 180A, 181, 184, or 2901.
Specifications
Pictures
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Left rear
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Left front
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Right front
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Right rear
