7912AD

Manuals – Specifications – Links – Pictures

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

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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