View source for 7912AD

{{Oscilloscope Sidebar 
|manufacturer=Tektronix 
|series=7000-series scopes
|model=7912AD
|summary=500 MHz digitizer
|image=Tek-7912ad.jpg
|caption=Tektronix 7912AD with [[7A26]] and [[7B90P]] 
|introduced=1978
|discontinued=1989 
|designers=Carlo Infante;Jim Cavoretto;Al Allworth;Don Roberts;Stu McNaughton;Walt Lowy;Ray Hayes;Ken Hawken;Bob Culter;Hal Cobb;Ed Ritz;Bo Janko
|manuals=
* ''complete manual needed, please add'' [[Category:Manual needed]]
* [[Media:7912AD theory.pdf|7912AD Operator's Manual]]<br /><small>(partial, 57 pages from introduction)</small>
* [[Media:7912AD reading gun supply.pdf|7912AD video preamp/reading gun supply schematics]]
* [[Media:7912AD writing gun supply.pdf|7912AD Z-Axis/HV board schematics]]

* [[Media:070-5077-00.pdf|Tektronix 7912AD Instrument Interfacing Guide]]
* [[Media:47W-5355.pdf|Tektronix 7912AD Brochure]]
{{ROM Images}}
* U900:  [[Media:160-1900-00.bin|160-1900-00]]
* U1000: [[Media:160-1899-00.bin|160-1899-00]]
* U1200: [[Media:160-1901-00.bin|160-1901-00]]
}}
The '''Tektronix 7912AD''' is a scan converter based digitizer in the [[7912|7912 series]] that succeeded the earlier [[R7912]] in 1978.

It has 500 MHz bandwidth, introduced a standard [[GPIB interface]] into the 7912 series, and could drive X-Y monitors directly. 
In contrast to the earlier R7912, the readout characters in video mode were created digitally and directly injected into the video signal.

For the 7912AD and 7912HB, special GPIB-controllable plug-in modules with a 'P' (Programmable) suffix were available, e.g. [[7A16P]], [[7A29P]] and [[7B90P]].

The 7912AD was succeeded by the 750 MHz '''7912HB''' in 1987 (using a [[7A29P]] amplifier). 

{{MissingSpecs}}

===Options===
* Option 4: Change to fast digitize mode. This option trades off scan time with resolution by compressing the scan. The target is written on and read from a 256 x 256 point matrix with a maximum of 14 points stored per vertical scan. This option is achieved by setting the correct jumpers on the A16, A20, A22, A26, A46 boards.
* Option 13: Changes the video output to 625 lines/frame with a 50 Hz field rate (PAL). This option is achieved by setting the correct jumpers on the A20 and A28 boards.

==Internals==
Three output methods are provided: Video (NTSC or PAL), X-Y-Z low-speed analog, and a [[GPIB interface]]. For video-out, Tektronix recommended the [[634|634 monitor]] or a monitor from the 650- and 670-series and a 75 Ω termination. For X-Y-Z analog, Tek recommended a 600-series monitor and no specific termination requirement.   

With aftermarket modifications to the electronics, 7912AD bandwidths have been extended up to 3 GHz in special cases.

==Links==
* [[Media:Rochester LLE Review Volume 25.pdf|University of Rochester LLE Review, Oct-Dec 1985]] mentioning the '''LM7912A''', a Lockheed-modified R7912 variant having ''"a bandwidth of 3.5 GHz at the -3 dB point, less than 5% undershoot and overshoot, with a 12-bit output (2 mV/bit)"''
* [[Media:Lockheed report-lmsc-d628276.pdf|Lockheed Palo Alto Research Lab study for LLL (June 1978)]] describing the LM7912 Enhanced Performance Transient Digitizer, claiming 3 GHz bandwidth
* [[Media:Boyer data acq ebeam fus acc.pdf|William B. Boyer, ''Data Acquisition and Processing on Electron Beam Fusion Accelerators''. IEEE Transactions on Nuclear Science Vol.NS-25, No. 1, February 1978]]
* [[Media:SAND94-0784.pdf|William B. Boyer, ''Overview of the Instrument Control and Data Reduction Software in the Sandia Data Acquistion System at the Nevada Test Site]]
* [[Media:Jonathan scott MESCthesis.pdf|Thesis on "7912ADM" upgrade version, Jonathan B. Scott]]
* [[Media:RISOM2873.pdf|''Improvement of the Bandwidth of the Transient Digitizers in the LIDAR Thomson Scattering Diagnostic on JET''. Risø National Laboratory, Denmark, June 1990]] discussing how removing the delay line and replacing the compensation circuit can boost the 7912AD+7A29 combination to 1.1 GHz bandwidth
* [https://www.radiomuseum.org/r/tektronix_7912ad.html Tek 7912AD @ radiomuseum.org]
{{Documents|Link=7912AD}}

==See Also==
* [[R7912]], [[7912HB]]
* [[WP2051]], [[WP2052]]
* [[MP1101]]
* [[SCD1000]], [[SCD5000]]
* [[670-6466-00]] 7912 AD plug-in interface extender
* [[067-0854-00]] Calibration Kit
* [[067-0679-99]] R7912 Demo Unit

==Pictures==

<gallery>
Tek-7912ad.jpg|7912AD front
7912AD_Front.jpg |7912AD front
7912ad.jpg|7912AD |7912AD front
7912AD_Rear.jpg|7912AD rear
Tek7912AD Top.JPG | 7912AD top view, cover removed
7912AD_Top.jpg | 7912AD top view, cover removed
7912AD_Top_detail.jpg| 7912AD top detail with A34 vertical amp
7912AD_Right.jpg|7912AD right
7912AD_Bottom.jpg|7912AD bottom, cover removed
7912ad-block.png | 7912AD block diagram
7912ad tube.gif | 7912AD digitizer tube
TEK Tube7912 Pic5.jpg  | T7912 tube - read part (left), target (center), write part (right). See [[T7912]] article for more photos.
IMG 20130408 115501.jpg|7912AD TV output on NTSC monitor
7912AD_FrontPanel.jpg|7912AD Back side of front panel
7912AD_A10_rear.jpg|7912AD A10 rear
7912AD_A10_front.jpg|7912AD A10 front with buttons partially removed to access the [[150-0048-01]] lamps
7912AD_PowerSwitch.jpg |7912AD A12 power button PCB front
7912AD_PowerSwitch_dis2.jpg |7912AD A12 power button disassembled to access the [[150-0048-01]] lamp
7912AD_A12_PowerSwitchRear.jpg| 7912AD A12 power button PCB rear
7912AD_A16.jpg | 7912AD A16 Memory Control with [[82S185]] PROMs
Tek7912ad 5156 bot.jpg|7912AD A18 Data Memory
Tek7912ad 5156 top.jpg|7912AD A18 Data Memory with [[IM5610]] PROMs
Tek7912ad data buffer top.jpg|7912AD A20 data buffer
Tek7912ad data buffer bot.jpg|7912AD A20 data buffer
Tek7912ad translator top.jpg|7912AD A22 translator
Tek7912ad translator bot.jpg|7912AD A22 translator
Tek7912ad graticule gen top.jpg|7912AD A24 graticule generator
Tek7912ad graticule gen bot.jpg|7912AD A24 graticule generator
Tek7912ad x-y ramp gen top.jpg|7912AD A26 X-Y ramp generator
Tek7912ad x-y ramp gen bot.jpg|7912AD A26 X-Y ramp generator
Tek7912ad video proc top.jpg|7912AD A28 video processor
Tek7912ad 4377.jpg|7912AD A32 Video preamp
Tek7912ad horiz.jpg|7912AD A40 horizontal
Tek7912ad scan amp.jpg|7912AD A38 scan amplifier
Tek7912ad mpu top.jpg|7912AD A54 MPU (new version with [[Motorola 6802|6802]] CPU SN B111166up)
Tek7912ad mpu bot.jpg|7912AD A54 MPU (new version with [[Motorola 6802|6802]] CPU SN B111166up)
Tek7912ad ieee488 top.jpg|7912AD A56 IEEE 488
Tek7912ad ieee488 bot.jpg|7912AD A56 IEEE 488
Tek 7912AD-670-5157-00-power-connector-pcb 1.jpg|7912AD A62 power connector PCB
Tek 7912AD-670-5157-00-power-connector-pcb 2.jpg|7912AD A62 power connector PCB
Tek 670-6466-00 1.jpg | 670-6466-00 plug-in extender
</gallery>

==Components==
{{Parts|7912AD}}

[[Category:7000 series digitizer mainframes]]
[[Category:Scan converter based instruments]]
[[Category:GPIB interface]]