7A12: Difference between revisions
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|designers=Roy Hayes | |designers=Roy Hayes | ||
|manuals= | |manuals= | ||
* [[Media:070-0977-01.pdf|Tektronix 7A12 Manual]] ( | * [[Media:070-0977-01.pdf|Tektronix 7A12 Manual]] (OCR) | ||
* [http://bama.edebris.com/download/tek/7a12/tek-7a12.pdf Tektronix 7A12 Manual @ BAMA] | <small> | ||
'''Alternate''' | |||
* [http://bama.edebris.com/download/tek/7a12/tek-7a12.pdf Tektronix 7A12 Manual @ BAMA] | |||
</small> | |||
}} | }} | ||
The '''Tektronix 7A12''' is a 120 MHz dual-trace vertical plug-in for [[7000-series scopes]]. This original 7000-series plugin allows | The '''Tektronix 7A12''' is a 120 MHz dual-trace vertical plug-in for [[7000-series scopes]]. This original 7000-series plugin allows large dc offset voltages, however the offset voltage is not available on the front panel to be measured externally as with the [[7A11]]. | ||
Switches on the front panel control [[miniature relays]] in the signal path | Switches on the front panel control [[miniature relays]] in the signal path to select input attenuators, through logic circuits. | ||
The 7A12 was designed by [[Roy Hayes]] (who also designed the [[3A3]] and [[3A8]] before leaving for HP Loveland in Jan 1971). | The 7A12 was designed by [[Roy Hayes]] (who also designed the [[3A3]] and [[3A8]] before leaving for HP Loveland in Jan 1971). | ||
The Evaluation Engineer for the 7A12 was [[Peter Starič]], co-author of the book "Wideband Amplifiers" with Erik Margan. | The Evaluation Engineer for the 7A12 was [[Peter Starič]], co-author of the book "Wideband Amplifiers" with Erik Margan. Peter and his daughter, Zorana, returned to Ljubljana on August 4, 1970. | ||
{{BeginSpecs}} | {{BeginSpecs}} | ||
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{{Spec | DC offset | At least ±500 divisions}} | {{Spec | DC offset | At least ±500 divisions}} | ||
{{EndSpecs}} | {{EndSpecs}} | ||
==Internals== | |||
The 7A12 uses the [[155-0032-00]] as a gain stage and the [[155-0022-00]] for channel switching. | |||
There were two mistakes, concept errors, that doomed the 7A12 from day one. The first was in deciding to use the 1 GHz F<sub>T</sub> Tektronix IC process (called 50/450 for resistivities of the two base layers) for the signal path. This process was too slow for a plugin expected to provide 150 MHz bandwidth in the fastest original mainframe, the [[7704]]. | |||
The second day one mistake, later pointed out by [[Tom Rousseau]], was to arrange the two channels side by side. Roy wanted to be able to go from one sensitivity (deflection factor) to another without having to go through all the sensitivities in between as happens with a rotary switch. The vertical row of push buttons was functionally attractive. However, that would require both channels to occupy the same space on a single vertical circuit board. | |||
The solution was two separate, mirror image attenuators and two identical amplifier boards all attached to a main vertically-centered circuit board. Having two mirror image attenuators was obviously very expensive. | |||
The two identical amplifier circuit boards, one mounted on each side of the center board, are cleverly flipped so both face outward from the center board. This is accomplished by having one near the top rail and the other near the bottom rail. | |||
Tom Rousseau designed a new dual trace plugin with discrete components on a single circuit board. One channel was above the other. This was all done on a single circuit board, had only 80 MHz bandwidth but was much less expensive to manufacture. He did this on his own, not at management's request. Management liked it and it became the [[7A18]]. Later Tom had the advantage of a 3 GHz IC process (SHF2). He used the [[M84]] (155-0078-xx), already in production for the [[485]], and it had circuitry similar to the 7A18. This was the 200 MHz [[7A26]]. It became the best selling Tektronix plugin of all time. Tektronix literally gold plated a 7A26 and gave it to Tom in recognition. | |||
See https://vintagetek.org/100000-7a26-plug-in/ | |||
==Links== | ==Links== | ||
* [ | * [https://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_amplifier/amplifier_7A12.htm 7A12 page @ amplifier.cd] | ||
* [http://www.barrytech.com/tektronix/tek7000/tek7a12.html 7A12 page @ barrytech.com] | * [http://www.barrytech.com/tektronix/tek7000/tek7a12.html 7A12 page @ barrytech.com] | ||
{{Documents|Link=7A12}} | |||
==Pictures== | ==Pictures== | ||
Line 46: | Line 64: | ||
</gallery> | </gallery> | ||
{{ | ==Components== | ||
{{Parts|7A12}} | |||
[[Category:7000 series vertical plugins]] | [[Category:7000 series vertical plugins]] |
Latest revision as of 00:20, 12 September 2024
The Tektronix 7A12 is a 120 MHz dual-trace vertical plug-in for 7000-series scopes. This original 7000-series plugin allows large dc offset voltages, however the offset voltage is not available on the front panel to be measured externally as with the 7A11.
Switches on the front panel control miniature relays in the signal path to select input attenuators, through logic circuits.
The 7A12 was designed by Roy Hayes (who also designed the 3A3 and 3A8 before leaving for HP Loveland in Jan 1971). The Evaluation Engineer for the 7A12 was Peter Starič, co-author of the book "Wideband Amplifiers" with Erik Margan. Peter and his daughter, Zorana, returned to Ljubljana on August 4, 1970.
Key Specifications
Bandwidth | 120 MHz (79xx) / 105 MHz (77xx) / 55 MHz (74xx) |
---|---|
Deflection | 5 mV/Div to 5 V/Div (1–2–5), variable up to 12.5 V/Div |
Input impedance | 1 MΩ // 24 pF |
Timing | Delay difference between channels < 500 ps |
Channel isolation | At least 3000:1 at 75 MHz |
Maximum input | 350 V DC + Peak AC at 1 kHz or less |
DC offset | At least ±500 divisions |
Internals
The 7A12 uses the 155-0032-00 as a gain stage and the 155-0022-00 for channel switching.
There were two mistakes, concept errors, that doomed the 7A12 from day one. The first was in deciding to use the 1 GHz FT Tektronix IC process (called 50/450 for resistivities of the two base layers) for the signal path. This process was too slow for a plugin expected to provide 150 MHz bandwidth in the fastest original mainframe, the 7704.
The second day one mistake, later pointed out by Tom Rousseau, was to arrange the two channels side by side. Roy wanted to be able to go from one sensitivity (deflection factor) to another without having to go through all the sensitivities in between as happens with a rotary switch. The vertical row of push buttons was functionally attractive. However, that would require both channels to occupy the same space on a single vertical circuit board.
The solution was two separate, mirror image attenuators and two identical amplifier boards all attached to a main vertically-centered circuit board. Having two mirror image attenuators was obviously very expensive.
The two identical amplifier circuit boards, one mounted on each side of the center board, are cleverly flipped so both face outward from the center board. This is accomplished by having one near the top rail and the other near the bottom rail.
Tom Rousseau designed a new dual trace plugin with discrete components on a single circuit board. One channel was above the other. This was all done on a single circuit board, had only 80 MHz bandwidth but was much less expensive to manufacture. He did this on his own, not at management's request. Management liked it and it became the 7A18. Later Tom had the advantage of a 3 GHz IC process (SHF2). He used the M84 (155-0078-xx), already in production for the 485, and it had circuitry similar to the 7A18. This was the 200 MHz 7A26. It became the best selling Tektronix plugin of all time. Tektronix literally gold plated a 7A26 and gave it to Tom in recognition.
See https://vintagetek.org/100000-7a26-plug-in/
Links
Documents Referencing 7A12
Document | Class | Title | Authors | Year | Links |
---|---|---|---|---|---|
Tekscope 1969 V1 N5 Oct 1969.pdf | Article | Introducing the New Generation | 1969 | 7000-series scopes • 7504 • 7704 • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7S11 • 7M11 • 7B50 • 7B51 • 7B70 • 7B71 • 7T11 • R5030 • 7000 series readout system • Miniature relays • Cam switches • Industrial Design • T7500 • T7700 • P6052 • P6053 • C-50 • C-51 • 204-2 | |
Tekscope 1969 V1 N6 Dec 1969.pdf | Article | A New Logic for Oscilloscope Displays | 1969 | 7000-series scopes • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7B50 • 7B51 • 7B70 • 7B71 • 7S11 • 7T11 • 7504 • 7704 | |
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 |
Pictures
-
Front view
-
Front view
-
Attenuator schematic with relays
-
7A12 Amplifier PCB
-
Left side view
Components
Some Parts Used in the 7A12
Part | Part Number(s) | Class | Description | Used in |
---|---|---|---|---|
148-0034-01 | 148-0034-01 | Discrete component | miniature DPDT relay | 485 • 7A12 |
148-0034-02 | 148-0034-02 | Discrete component | miniature DPDT relay | 7A12 |
155-0022-00 | 155-0022-00 • 155-0022-01 | Monolithic integrated circuit | analog multiplexer | 147 • 148 • 149 • 335 • 468 • 1430 • 1441 • 1461 • 1900 • 1910 • 2220 • 2221 • 2230 • 5223 • 5403 • 5440 • 5441 • 5443 • 5444 • 5A38 • 7313 • 7403N • 7503 • 7504 • 7514 • 7603 • AN/USM-281C • 7613 • 7623 • 7623A • 7633 • 7704 • R7704 • 7704A • 7834 • 7844 • 7854 • R7912 • 7912AD • 7912HB • 7904 • R7903 • 7904A • 7934 • 7A12 • 7A18 • 7A18A • 7A18N • 7B52 • 7B53N • 7D10 • 7D11 • 7D12 • NT-7000 • P7001 |
155-0032-00 | 155-0032-00 • 155-0032-01 | Monolithic integrated circuit | variable-gain transconductance (current output with voltage input) amplifier | 335 • 464 • 465 • 465B • 466 • 475 • 475A • 475M • 634 • 650 • 651 • 652 • 653 • 655 • 656 • 670 • 671 • 7A12 • 475 • FG504 • 1440 • 1460 • 1480 • 1481 • 1482 • 1485 |