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The Tektronix 7B92 is a 500 MHz timebase plug-in for [[7000-series scopes]].
{{Plugin Sidebar 
|manufacturer=Tektronix
|type=7B92
|summary=500 MHz dual timebase
|image=Tek 7b92 front.jpg
|caption=7B92 front
|introduced=1971
|discontinued=1976
|series=7000-series scopes
|designers=Bill DeVey;Val Garuts
|manuals=
'''7B92'''
* [[Media:070-1401-00.pdf|Tektronix 7B92 Operators Manual]]
* [[Media:070-1192-00.pdf|Tektronix 7B92 Service Manual]] (OCR, uncut schematics)
* [[Media:070-1630-00.pdf|Tektronix 7B92 Circuit Description Supplement]]
}}
The '''Tektronix 7B92''' is a 500 MHz dual timebase plug-in for [[7000-series scopes]].
It was introduced along with the [[7904]] mainframe in 1972.
According to [[Media:Tekscope 1971 V3 N4 Jul 1971.pdf|July 1971 Tekscope]], the 7B92 was designed by [[Les Larson]] and [[Bill DeVey]].  


The 7B92 uses a discrete trigger circuit containing [[tunnel diodes]].
An "HF Sync" triggering mode is provided in which the trigger level control varies the frequency of a built-in oscillator to lock on to the input for input signals from 100 to 500 MHz, providing higher sensitivity than the direct trigger (which is specified up to 500 MHz as well).


Up to serial number B069999, the 7B92A a discrete trigger circuit.
Internal jumpers are provided to configure the 7B92 for operation in 7800/7900 vs. slower mainframes, and to select whether the variable control affects the delaying or the delayed time base.
After that, the 7B92A uses a [[155-0061-00]] trigger amplifier followed by a
[[155-0150-00]] trigger detector.


* [http://bama.edebris.com/download/tek/7b92a-2/tek-7b92a.pdf Tektronix 7B92A Manual (PDF)]
As a dual time base, the 7B92 uses the top field in the [[7000 series readout system|display readout]] for the sweep speed of the main and the bottom field for the delayed time base.
* [http://w140.com/smb/7b92_sup_sm.pdf Tektronix 7B92 Circuit Description Supplement (OCR, PDF)]
The delay time can only be read from the 10-turn analog dial.
* [http://w140.com/smb/7b92_svc_sm.pdf Tektronix 7B92 Service Manual (OCR, PDF)]
* [http://w140.com/smb/7b92a_op_sm.pdf Tektronix 7B92A Operators Manual (OCR, PDF)]
* [http://w140.com/smb/7b92a_sm.pdf Tektronix 7B92A Service Manual (OCR, PDF)]


The 7B92 has no magnifier function but its regular sweep dial setting reaches down to 500 ps/Div.  It has no provision for X-Y operation.


{{BeginSpecs}}
{{Spec | Sweep speed    | 0.5 ns/Div to 0.2 s/Div, 1−2−5 sequence (variable up to 0.5 s/Div)}}
{{Spec | Delay time    | 0 to 9.9 Div }}
{{Spec | Triggering    | 0.5 Div or 100 mV up to 20 MHz, 1 Div or 500 mV up to 600 MHz }}
{{Spec | Jitter        | < 50 ps at 600 MHz }}
{{Spec | Ext Trig input | 1 MΩ // 20 pF or 50 Ω }}
{{EndSpecs}}
After the 7B92 had been in production for years, it was discovered that the 7B92's ramp generator
had aberrations at the beginning of the sweep at the fastest sweep rates.
[https://vintagetek.org/years-at-tektronix-hofer/ Bruce Hofer recalls] investigating this issue and
concluding that an redesign was needed.
The redesign led to the introduction of the [[7B92A]], [[Patent US 4009399A]],
and the [[067-0657-00]] calibration fixture.
==Links==
{{Documents|Link=7B92}}
{{PatentLinks|7B92}}
==Internals==
The 7B92 uses a discrete trigger circuit containing [[152-0177-02]] [[tunnel diodes]].
The internal jumper (J308/J309) for mainframe selection (7800/7900/7100 vs. slower)
increases the minimum holdoff time on the slower mainframe selection by adding a 150 pF capacitor, C307,
to pin 8 (HO TIMING) of the sweep control IC, U310 ([[155-0049-00|155-0049-xx]]), in parallel to the existing capacitors.
This increases the minimum pulse width of the holdoff signal on [[7000_Series_plug-in_interface|pin B4]]
so that the sweep logic of slower mainframes can handle it properly.
The effect of this jumper is only noticeable for sweep speeds of 20 μs/Div and faster,
since at those sweep speeds the smallest shunt capacitance is used on pin 8, and the holdoff time is minimal.
==Pictures==
<gallery>
<gallery>
File:Tek 7b92a front.jpg|7B92A front
Tek 7b92 front.jpg   | 7B92 front
Image:Tek 7b92a block.png
Tek 7b92 right.jpg    | 7B92 right
Tek 7b92 left.jpg    | 7B92 left
</gallery>
</gallery>
==Components==
{{Parts|7B92}}
[[Category:7000 series horizontal plugins]]

Latest revision as of 10:47, 19 June 2024

Tektronix 7B92
500 MHz dual timebase
7B92 front

Compatible with 7000-series scopes

Produced from 1971 to 1976

Manuals

7B92

(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix 7B92 is a 500 MHz dual timebase plug-in for 7000-series scopes. It was introduced along with the 7904 mainframe in 1972. According to July 1971 Tekscope, the 7B92 was designed by Les Larson and Bill DeVey.

An "HF Sync" triggering mode is provided in which the trigger level control varies the frequency of a built-in oscillator to lock on to the input for input signals from 100 to 500 MHz, providing higher sensitivity than the direct trigger (which is specified up to 500 MHz as well).

Internal jumpers are provided to configure the 7B92 for operation in 7800/7900 vs. slower mainframes, and to select whether the variable control affects the delaying or the delayed time base.

As a dual time base, the 7B92 uses the top field in the display readout for the sweep speed of the main and the bottom field for the delayed time base. The delay time can only be read from the 10-turn analog dial.

The 7B92 has no magnifier function but its regular sweep dial setting reaches down to 500 ps/Div. It has no provision for X-Y operation.

Key Specifications

Sweep speed 0.5 ns/Div to 0.2 s/Div, 1−2−5 sequence (variable up to 0.5 s/Div)
Delay time 0 to 9.9 Div
Triggering 0.5 Div or 100 mV up to 20 MHz, 1 Div or 500 mV up to 600 MHz
Jitter < 50 ps at 600 MHz
Ext Trig input 1 MΩ // 20 pF or 50 Ω

After the 7B92 had been in production for years, it was discovered that the 7B92's ramp generator had aberrations at the beginning of the sweep at the fastest sweep rates. Bruce Hofer recalls investigating this issue and concluding that an redesign was needed. The redesign led to the introduction of the 7B92A, Patent US 4009399A, and the 067-0657-00 calibration fixture.

Links

Documents Referencing 7B92

Document Class Title Authors Year Links
Tekscope 1971 V3 N4 Jul 1971.pdf Article A Subnanosecond Realtime Oscilloscope Val Garuts • Thor Hallen 1971 7904 • 154-0644-00 • 7A19 • Ft doubler • 7B92
7000 series brochure March 1973.pdf Brochure 7000 series brochure, March 1973 1973 7A11 • 7A12 • 7A13 • 7A14 • 7A15A • 7A16A • 7A17 • 7A18 • 7A19 • 7A21N • 7A22 • 7B50 • 7B53A • 7B70 • 7B71 • 7B92 • 7CT1N • 7D11 • 7D13 • 7D14 • 7D15 • 7M11 • 7L12 • 7S11 • 7S12 • 7T11 • 7704A • R7704 • 7904 • R7903 • 7603 • R7603 • 7403N • R7403N • 7313 • R7313 • 7613 • R7613 • 7623 • R7623 • P7001

Patents that may apply to 7B92

Page Title Inventors Filing date Grant date Links
Patent US 3562464A Cam actuated switch having movable and fixed contacts on circuit board Howard Vollum • Willem H Verhoef • Tony Sprando 1968-10-07 1971-02-09 Cam switches • 2101 • 2701 • 2703 • 432 • 434 • 465 • 475 • 5A15N • 5A18N • 5A20N • 5A21N • 5A38 • 5A45 • 5B10N • 5B12N • 7A15 • 7A16A • 7A18 • 7A19 • 7A24 • 7A26 • 7B10 • 7B15 • 7B50 • 7B51 • 7B52 • 7B53A • 7B50A • 7B70 • 7B71 • 7B80 • 7B85 • 7B87 • 7B92 • 7B92A • 7D01 • 7D12 • 7D15 • 7J20 • 7S12 • 7T11 • 7T11A • AF501 • AM502 • AM503 • DC502 • DC503 • DC504 • DC505 • DM501 • DM502 • FG501 • FG501A • FG502 • FG503 • FG504 • FG507 • PG501 • PG502 • PG505 • PG506 • PG506A • PG508 • TG501 • SC502 • SC503 • SC504
Patent US 3584174A Push-button switch apparatus having cam actuated switch contacts and selective illumination means Tony Sprando • Peter S Winkelmann 1969-06-09 1971-06-08 Back-lit switches • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A16P • 7A22 • 7A42 • 7B42N • 7B50 • 7B51 • 7B52 • 7B53A • 7B70 • 7B71 • 7B92 • 7B92A • 7D10 • 7D11 • 7D12 • 7D114 • 7D15 • 7D20 • 7F10 • 7L5 • 7L12 • 7L13 • 7L14 • 7L18 • 7M13 • 7S11 • 7S12 • 7T11 • 067-0587-00 • 067-0587-01 • 067-0587-02 • 067-0587-10

Internals

The 7B92 uses a discrete trigger circuit containing 152-0177-02 tunnel diodes.

The internal jumper (J308/J309) for mainframe selection (7800/7900/7100 vs. slower) increases the minimum holdoff time on the slower mainframe selection by adding a 150 pF capacitor, C307, to pin 8 (HO TIMING) of the sweep control IC, U310 (155-0049-xx), in parallel to the existing capacitors. This increases the minimum pulse width of the holdoff signal on pin B4 so that the sweep logic of slower mainframes can handle it properly. The effect of this jumper is only noticeable for sweep speeds of 20 μs/Div and faster, since at those sweep speeds the smallest shunt capacitance is used on pin 8, and the holdoff time is minimal.

Pictures

  • 7B92 front

    7B92 front

  • 7B92 right

    7B92 right

  • 7B92 left

    7B92 left

Components

Some Parts Used in the 7B92

Part Part Number(s) Class Description Used in
155-0061-00 155-0061-00 • 155-0061-01 • 155-0061-02 Monolithic integrated circuit trigger amplifier 7B92 • 7B92A
1N3719 152-0182-00 Discrete component 10 mA, 50 pF germanium tunnel diode 422 • 661 • 7B92 • 7B92A
SMTD998 152-0177-02 Discrete component 10 mA, 2 pF tunnel diode 067-0681-01 • 485 • 7B92 • 7B92A
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