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| {{Oscilloscope Sidebar| | | {{Oscilloscope Sidebar |
| title=Tektronix 7912|
| | |manufacturer=Tektronix |
| image=Tek-7912ad.jpg| | | |series=7000-series scopes |
| caption=Tektronix 7912AD with [[7A26]] and [[7B90P]] | | | |model=7912 |
| introduced=1973 | | | |summary=500/750 MHz digitizer |
| discontinued=1989 | | | |image=Tek-7912ad.jpg |
| summary=500/750 MHz Digitizer|
| | |caption=Tektronix 7912AD with [[7A26]] and [[7B90P]] |
| manuals= | | |introduced=1973 |
| '''R7912'''
| | |discontinued=1989 |
| * [[Media:R7912 070-1590-00.pdf|Tektronix R7912 Service Manual (PDF)]] | | |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 |
| * [[Media:1350 070-1888-00.pdf|1350 (AKA 067-0679-00) Memory Display Unit for R7912 (PDF)]]
| | |manuals= |
| * [[Media:Waveform Digitizing Instruments (R7912).pdf|Waveform Digitizing Instruments (R7912) Brochure (PDF)]]
| | * ''see individual model pages'' |
| * [http://w140.com/tek_7912_and_related_digitizer_docs.pdf 7912 and related digitizer documents]
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| '''7912AD/HB''' | |
| * [[Media:7912ad_theory.pdf | 7912AD Operator's Manual (partial, 57 pages from introduction)]]
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| * [http://w140.com/7912ad_reading_gun_supply.pdf 7912AD Video preamp/Reading gun supply schematics]
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| * [http://w140.com/7912ad_writing_gun_supply.pdf 7912AD Z-Axis/HV board schematics]
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| * [[Media:070-5077-00.pdf|Tektronix 7912AD Instrument Interfacing Guide (PDF)]]
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| }} | | }} |
| The '''Tektronix 7912''' is a series of high-speed digitizers that take one [[7000-series_plug-ins#Vertical plug-ins|7000-series vertical plug-in]] | | The '''Tektronix 7912''' is a series of high-speed digitizers that take one [[7000-series_plug-ins#Vertical plug-ins|7000-series vertical plug-in]] |
| and one [[7000-series_plug-ins#Horizontal plug-ins|7000-series horizontal plug-in]]. | | and one [[7000-series_plug-ins#Horizontal plug-ins|7000-series horizontal plug-in]]. The primary markets for the 7912 series were nuclear and laser research. |
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| All 7912 models use the same internal CRT-based, digitizing [[scan converter]] tube ([[T7912]]) that is not visible from the outside. | | All 7912 models use the same internal CRT-based, digitizing [[scan converter]] tube ([[T7912]], 154-0698-00) that is not visible from the outside. |
| The signal from the vertical plug-in deflects a writing beam through [[distributed deflection plates]]. | | The signal from the vertical plug-in deflects a writing beam through [[distributed deflection plates]]. |
| The electrons hit a small flat rectangular solid state target, conceptually similar to the image sensor in a digital camera. | | The electrons hit a small flat rectangular solid state target, conceptually similar to the image sensor in a digital camera. |
| The resolution of the target is 512×512, giving 512 points in the time domain and 9-bit linear quantization of the input voltage. | | The resolution of the target is 512×512, giving 512 points in the time domain and 9-bit linear quantization of the input voltage. |
| | With a [[7B92]] sweeping the whole X-axis in 5 ns, and the 7912 capturing 512 samples in that sweep, the 7912 performs the function of a 100 GSample/s A/D converter. |
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| With a [[7B92]] sweeping the whole X-axis in 5 ns, and the 7912 capturing 512 samples in that sweep,
| | ==7912 Series Models== |
| the 7912 performs the function of a 100 GSample/s A/D converter.
| | * The '''[[R7912]]''', introduced in September 1973 (Ref.1), achieved a bandwidth of 500 MHz with a [[7A19]] vertical amplifier plug-in. |
| | * The '''[[7912AD]]''' (1978) had 500 MHz bandwidth and introduced a standard [[GPIB interface]]. |
| | * The '''[[7912HB]]''' (1987) extended bandwidth to 750 MHz (using a [[7A29P]] amplifier). |
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| The primary markets for the 7912 series were nuclear and laser research. | | * The [[LM7912]] is a Tektronix R7912 modified by Lockheed Palo Alto Research Lab for extended bandwidth. |
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| ==R7912==
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| The '''R7912''', introduced in September 1973 (Ref.1), achieved a bandwidth of 500 MHz with a [[7A19]] vertical amplifier plug-in.
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| It was also possible, like in the [[7904]] scope, to access the CRT deflection plates directly through a [[7A21N]] plug-in and achieve a bandwidth of 1 GHz,
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| albeit at reduced sensitivity (4 V/Div) and loss of triggering and readout functions.
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| Some customers further modified the stock 7912 to increase bandwidth up to 3 GHz in special applications (see literature links below).
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| The reading beam operates differently depending on the output mode.
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| In TV mode, the reading beam scans the target in a horizontal format similar to that used in conventional television systems,
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| and a video output compatible with TV monitors is generated. In Digital mode, the reading beam scans the target vertically,
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| in 512 discrete steps for each of 512 horizontal positions.
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| Waveforms are converted to digital, stored in memory, and can be read by a computer.
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| The R7912 used the [[7000 series readout system]] writing readout characters onto the storage target,
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| which would become part of the output signal in the NON STORE mode.
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| The R7912 had a proprietary digital interface. A card for interfacing to a DEC PDP-11 was available.
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| The Tektronix 067-0679-00 Digital Display Controller is an external module that interfaces with the 7912 and an analog X-Y storage display ([[607?]]).
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| Tek also offered configurations with multiple R7912s on a common controller within the WP2000 series.
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| ==7912AD and 7912HB==
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| From the '''7912AD''' (1978) on, the instrument had a standard [[GPIB interface]].
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| The 7912AD has 500 MHz bandwidth. It was succeeded by the 750 MHz 7912HB in 1987 (using a [[7A29P]] amplifier).
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| For the 7912AD and 7912HB, special GPIB-controllable plug-in modules with a 'P' suffix, meaning Programmable,
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| were available, e.g. [[7A16P]], [[7A29P]] and [[7B90P]].
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| ===7912AD Options===
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| * 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.
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| * 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.
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| ==Internals==
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| Three output methods are provided: Video (NTSC or PAL), X-Y-Z low-speed analog, and a [[GPIB interface]]. For video-out Tektronix recommends the [[634|634 monitor]] or a monitor from the 650- and 670-series and a 75 Ω termination. For X-Y-Z analog Tek recommends a 600-series monitor and no specific termination requirement.
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| With aftermarket modifications to the electronics, 7912AD bandwidths have been extended up to 3 GHz in special cases.
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| ==Specifications==
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| The Tektronix 7912AD is 19" wide, 7" tall, 27" deep, and weighs 55 pounds. It uses 360 watts maximum.
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| ==Literature and Software==
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| # [http://tekretirees.org/Newsletter/nov2012_trn.pdf Hale Farley, ''The introduction of the R7912''] in Tek Retirees Newsletter 11/2012
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| # [http://w140.com/US3748585.pdf US Patent 3748585: ''Silicon Diode Array Scan Converter Tube and Method of Operation''. Culter et al, July 1973.]
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| # [http://pwww.lle.rochester.edu/media/publications/lle_review/documents/v25/25_Review.pdf 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)"''
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| # [http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/10/434/10434659.pdf Lockheed Palo Alto Research Lab study for LLL (June 1978)] describing the LM7912 Enhanced Performance Transient Digitizer, claiming 3 GHz bandwidth
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| # [http://w140.com/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]
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| # [http://www.scottpages.net/MESCthesis.pdf Thesis on "7912ADM" upgrade version]
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| # [http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Tek/Transient%20Digitizers/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
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| # [http://w140.com/kurt/7912_gpib_examples.zip 7912 GPIB examples]
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| ==Links==
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| * [[Carlo Infante]]: A New Way to Look At Transients (R7912). In [[Media:Tekscope 1973 V5 N6 Nov 1973.pdf | TekScope Vol. 5 No. 6, Nov-Dec 1973]]
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| * [http://www.radiomuseum.org/forum/tektronix_r7912_transient_digitizer.html Tek R7912 @ radiomuseum.org]
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| * [[Dale Aufrecht]]: An Intelligent, Programmable Transient Digitizer (7912AD). In [[Media:Tekscope 1979 V11 N1.pdf | TekScope Vol. 11 No. 1, 1979]]
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| * [http://www.radiomuseum.org/r/tektronix_7912ad.html Tek 7912AD @ radiomuseum.org]
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| ==See Also==
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| * [[WP2051]], [[WP2052]]
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| * [[SCD1000]], [[SCD5000]]
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| * [[670-6466-00]] 7912 AD plug-in interface extender
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| * [[067-0854-00]] Calibration Kit
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| ==Pictures==
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| ===R7912===
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| <gallery>
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| USA Tek R7912 FrontWork.jpg | R7912 connected to a modern video monitor. Note 7000-style readout.
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| R7912 1.jpg | R7912 front
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| R7912 2.jpg | R7912 controls
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| R7912 3.jpg | R7912 rear
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| Tek wp2000 2.jpg|WP 2000 front next to [[608]] monitor
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| Tek wp2000 3.jpg|WP 2000 rear next to [[608]] monitor
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| Tek wp2000 1.jpg|WP 2000 detail
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| </gallery>
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| ===7912AD===
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| <gallery>
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| 7912ad tube.gif | 7912AD digitizer tube
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| TEK Tube7912 Pic5.jpg | T7912 tube - read part (left), target (center), write part (right). See [[T7912]] article for more photos.
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| 7912ad-block.png | 7912AD block diagram
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| 7912ad.jpg|7912AD front
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| IMG 20130408 115501.jpg|7912AD TV output on NTSC monitor
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| Tek7912AD Top.JPG | 7912AD top view, cover removed
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| Tek7912ad ieee488 top.jpg|7912AD IEEE 488
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| Tek7912ad ieee488 bot.jpg|7912AD IEEE 488
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| Tek7912ad mpu top.jpg|7912AD MPU
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| Tek7912ad mpu bot.jpg|7912AD MPU
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| Tek7912ad 5156 bot.jpg|7912AD 5156
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| Tek7912ad 5156 top.jpg|7912AD 5156
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| Tek7912ad data buffer top.jpg|7912AD data buffer
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| Tek7912ad data buffer bot.jpg|7912AD data buffer
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| Tek7912ad translator top.jpg|7912AD translator
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| Tek7912ad translator bot.jpg|7912AD translator
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| Tek7912ad graticule gen top.jpg|7912AD graticule generator
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| Tek7912ad graticule gen bot.jpg|7912AD graticule generator
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| Tek7912ad x-y ramp gen top.jpg|7912AD X-Y ramp generator
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| Tek7912ad x-y ramp gen bot.jpg|7912AD X-Y ramp generator
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| Tek7912ad video proc top.jpg|7912AD video processor
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| Tek7912ad 4377.jpg|7912AD 4377
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| Tek7912ad horiz.jpg|7912AD horizontal
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| Tek7912ad scan amp.jpg|7912AD scan amplifier
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| Tek 670-6466-00 1.jpg | 670-6466-00 plug-in extender
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| Tek 7912AD-670-5157-00-power-connector-pcb 1.jpg|7912AD power connector PCB
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| Tek 7912AD-670-5157-00-power-connector-pcb 2.jpg|7912AD power connector PCB
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| </gallery>
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| ===7912HB===
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| <gallery>
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| Tek 7912hb 1.jpg|7912HB
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| Tek 7912hb 2.jpg|7912HB
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| Tek 7912hb 3.jpg|7912HB
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| Tek 7912hb 4.jpg|7912HB
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| </gallery>
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| | ==Project Staff== |
| | * [[Carlo Infante]], Program manager |
| | * [[Jim Cavoretto]], Project Engineer |
| | * [[Al Allworth]], [[Don Roberts]], and [[Stu McNaughton]], Electrical Engineers |
| | * [[Walt Lowy]], Engineering Technician |
| | * [[Ray Hayes]], [[Ken Hawken]], [[Bob Culter]], [[Hal Cobb]], [[Ed Ritz]], and [[Bo Janko]], CRT Engineering |
| | * [[Loyal Strom]], [[Helene Albright]] and [[Ken Nesvold]], Prototype Support |
| | * [[Doug Giesbers]], [[Larry Pearson]] and [[Phil Lloyd]], Mechanical Engineering |
| | * [[Nick Hughes]] and [[Ray Blohm]], Instrument Manufacturing |
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| [[Category:7000 series digitizer mainframes]] | | [[Category:7000 series digitizer mainframes]] |
| [[Category:Scan converter based instruments]] | | [[Category:Scan converter based instruments]] |
| [[Category:Specifications needed]]
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| [[Category:GPIB interface]]
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