7912AD
The Tektronix 7912AD is a scan converter based digitizer in the 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).
Key Specifications
- please add
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 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
- 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)"
- Lockheed Palo Alto Research Lab study for LLL (June 1978) describing the LM7912 Enhanced Performance Transient Digitizer, claiming 3 GHz bandwidth
- William B. Boyer, Data Acquisition and Processing on Electron Beam Fusion Accelerators. IEEE Transactions on Nuclear Science Vol.NS-25, No. 1, February 1978
- William B. Boyer, Overview of the Instrument Control and Data Reduction Software in the Sandia Data Acquistion System at the Nevada Test Site
- Thesis on "7912ADM" upgrade version, Jonathan B. Scott
- 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
- Tek 7912AD @ radiomuseum.org
Documents Referencing 7912AD
| Document | Class | Title | Authors | Year | Links |
|---|---|---|---|---|---|
| Tekscope 1979 V11 N1.pdf | Article | An Intelligent, Programmable Transient Digitizer | Dale Aufrecht | 1979 | 7912AD • 7A16P • 7B90P |
| RISOM2873.pdf | Article | Improvement of the Bandwidth of the Transient Digitizers in the LIDAR Thomson Scattering Diagnostic on JET | Erik Kristensen | 1990 | 7912AD • 7A29 • 7704A • 7S12 • S-6 • S-52 |
Patents that may apply to 7912AD
| Page | Title | Inventors | Filing date | Grant date | Links |
|---|---|---|---|---|---|
| Patent US 3748585A | Silicon diode array scan converter storage tube and method of operation | Robert G. Culter • Raymond Hayes • Emmanuel Sang | 1971-11-15 | 1973-07-24 | 7912 • T7912 • R7912 • 7912AD • 7912HB • Scan converter |
| Patent US 3796910A | Electron beam deflection system | Ed Ritz | 1972-08-04 | 1974-03-12 | 7912 • T7912 • R7912 • 7912AD • 7912HB |
| Patent US 3893036A | Precision function generator | Jim Cavoretto • Al Allworth • Carlo Infante | 1973-07-27 | 1975-07-01 | 7912 • T7912 • R7912 • 7912AD • 7912HB |
See Also
- R7912, 7912HB
- MP1101
- SCD1000, SCD5000
- 670-6466-00 7912 AD plug-in interface extender
- 067-0854-00 Calibration Kit
Pictures
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7912AD front
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7912AD front
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7912AD front
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7912AD rear
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7912AD top view, cover removed
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7912AD top view, cover removed
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7912AD top detail with A34 vertical amp
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7912AD right
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7912AD bottom, cover removed
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7912AD block diagram
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7912AD digitizer tube
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T7912 tube - read part (left), target (center), write part (right). See T7912 article for more photos.
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7912AD TV output on NTSC monitor
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7912AD Back side of front panel
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7912AD A10 rear
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7912AD A10 front with buttons partially removed to access the 150-0048-01 lamps
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7912AD A12 power button PCB front
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7912AD A12 power button disassembled to access the 150-0048-01 lamp
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7912AD A12 power button PCB rear
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7912AD A16 Memory Control with 82S185 PROMs
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7912AD A18 Data Memory
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7912AD A18 Data Memory with IM5610 PROMs
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7912AD A20 data buffer
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7912AD A20 data buffer
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7912AD A22 translator
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7912AD A22 translator
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7912AD A24 graticule generator
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7912AD A24 graticule generator
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7912AD A26 X-Y ramp generator
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7912AD A26 X-Y ramp generator
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7912AD A28 video processor
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7912AD A32 Video preamp
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7912AD A40 horizontal
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7912AD A38 scan amplifier
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7912AD A54 MPU (new version with 6802 CPU SN B111166up)
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7912AD A54 MPU (new version with 6802 CPU SN B111166up)
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7912AD A56 IEEE 488
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7912AD A56 IEEE 488
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7912AD A62 power connector PCB
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7912AD A62 power connector PCB
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670-6466-00 plug-in extender
