7D20: Difference between revisions

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The Tektronix 7D20 is a two-channel digitizing plug-in for 7000-series mainframes.  It provides both vertical and horizontal signals to the scope.  The 7D20 uses an analog shift register for high-speed signal acquisition, and then digitizes the stored analog signal at a lower speed.  This allowed the 7D20 to capture single-shot events at 40Msamp/sec even though exceeded the speed of ADCs of the time.  The 7D20 can digitally store waveforms and has GPIB.
{{Plugin Sidebar
|manufacturer=Tektronix
|series=7000-series scopes
|type=7D20
|summary=70 MHz dual-channel digitizer
|image=tek-7603-7d20.jpg
|caption=7D20 in [[7603]] mainframe
|introduced=1982
|discontinued=1992
|manuals=
* [[Media:070-3205-01.pdf|Tektronix 7D20 Reference Guide]]
* [[Media:070-3857-01.pdf|Tektronix 7D20 Operators Manual]] (OCR)
* [[Media:070-3858-01.pdf|Tektronix 7D20 Service Manual]] (OCR, split schematics, standard resolution)
* [[Media:070-3858-01 lowres.pdf|Tektronix 7D20 Service Manual]] (OCR, whole schematics, low resolution)
* [[Media:070-1728-00.pdf|Tektronix 7D20 Interfacing Guide]]
* [[Media:7D20 SMPS AnalysisDFT Apr1984.pdf|EDN Article by Clark Foley and Jim Lamb on SMPS diagnosis featuring the 7D20]]
 
{{ROM Images}}
* U200: [[Media:160-1164-02.bin|160-1164-02]]
* U300: [[Media:160-1165-02.bin|160-1165-02]]
* U400: [[Media:160-1163-02.bin|160-1163-02]]
* U500: [[Media:160-1162-03.bin|160-1162-03]]
* U600: [[Media:160-1676-02.bin|160-1676-02]]
* U700: [[Media:160-1757-03.bin|160-1757-03]]
}}
The '''Tektronix 7D20''' is a two-channel digitizing plug-in for [[7000-series scopes]].  It is a triple-width plug-in and provides both vertical and horizontal signals to the scope. The 7D20 can digitally store waveforms and has a [[GPIB interface]].
 
A special version of the rackmount large screen [[R7603]] exists (Opt. 20), which provides a rear-panel [[GPIB]] connector to be used with the 7D20. 
 
{{BeginSpecs}}
{{Spec| Bandwidth      | 0–70 MHz (DC), 10 Hz–70 MHz (AC) }}
{{Spec| Rise time      |  < 5 ns }}
{{Spec| Sampling Rate  |  40 MSps }}
{{Spec| Resolution      |  8 bit }}
{{Spec| Deflection      |  5 mV/Div to 5 V/Div (1–2–5) }}
{{Spec| Input impedance |  1 MΩ // 20 pF }}
{{Spec| Time base |
* 50 ns/Div — 1 μs/Div: Equivalent Time Mode
* 2 μs/Div — 200 μs/Div: Extended Real Time Mode
* 500 μs/Div — 50 ms/Div: Real Time Mode
* 100 ms/Div — 20 s/Div and External: Roll Mode
}}
{{Spec| External clock  |  < 10 kHz }}
{{Spec| Memory          |  2 × 455 cells (alternating) analog / 1024 words digital }}
{{Spec| Features |
* 2 channels
* 6 memory banks
* 2 cursors
}}
{{Spec| Weight | 3.9 kg (8.5 lb) }}
{{EndSpecs}}
 
==Internals==
 
The 7D20 uses an analog shift register (CCD) for high-speed signal acquisition, and then digitizes the stored analog signal at a lower speed (see [[Patent US 4527117A]]).  This design allowed the 7D20 to capture single-shot events at 40 MSamples/s even though this exceeded the speed of ADCs of the time.  A microprocessor ([[Motorola 6809|68B09]]) in the plug-in controls most of its functions. 
 
The analog waveforms that are sent to the 7000-series mainframe are generated by vertical and horizontal DACs.  The DACs outputs can be calibrated for scaling and shift so that signals are accurately displayed on the oscilloscope screen. 
 
The 7D20 has a "roll" mode that emulates a paper roll chart, as if the waveform were being drawn by a pen on the right side of the screen while the paper is being moved to the left at a constant rate. No equivalent to "roll" exists in analog scopes.  The Tektronix [[2212]]/[[2216]], [[2220]]/[[2221]]/[[2230]] and possibly others also have this feature.
 
The 7D20 can give [[NVRAM errors]] that are often easy to fix.
 
==Links==
 
* [http://amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_special/scope_7D20.htm 7D20 page @ amplifier.cd]
* [http://www.jvgavila.com/tek7603.htm EB5AGV's Tektronix R7603 / 7D20 page] - 7D20+[[R7603]] Repair Report
* [http://pcbunn.cithep.caltech.edu/jjb/tektronix/7D20/tektronix_7d20.htm Another 7D20 repair]
* [http://www.barrytech.com/tektronix/tek7000/tek7d20.html 7D20 @ barrytech.com]
 
==Pictures==
 
<gallery>
tek-7603-7d20.jpg
7d20 plugin.jpg
Tek 7d20 1.jpg
Tek7d20.jpg
7d20-manual.jpg | 7D20 picture from manual
7d20-in-mf-manual.jpg| 7D20 picture in 7603 mainframe, from manual
Tek 7d20 rear.jpg
Tek 7d20 2.jpg
Tek 7d20 3.jpg
Tek 7d20 4.jpg
Tek 7d20 5.jpg
Tek 7d20 6.jpg
Tek 7d20 7.jpg
Tek 7d20 8.jpg
Tek 7d20 9.jpg
</gallery>
 
==Parts==
{{Parts|7D20}}
 
[[Category:7000 series combined plugins]]
[[Category:Digital storage scopes]]
[[Category:GPIB interface]]

Latest revision as of 08:57, 7 December 2023

Tektronix 7D20
70 MHz dual-channel digitizer
7D20 in 7603 mainframe

Compatible with 7000-series scopes

Produced from 1982 to 1992

Manuals
ROM Images
File Pos. Checksum
(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix 7D20 is a two-channel digitizing plug-in for 7000-series scopes. It is a triple-width plug-in and provides both vertical and horizontal signals to the scope. The 7D20 can digitally store waveforms and has a GPIB interface.

A special version of the rackmount large screen R7603 exists (Opt. 20), which provides a rear-panel GPIB connector to be used with the 7D20.

Key Specifications

Bandwidth 0–70 MHz (DC), 10 Hz–70 MHz (AC)
Rise time < 5 ns
Sampling Rate 40 MSps
Resolution 8 bit
Deflection 5 mV/Div to 5 V/Div (1–2–5)
Input impedance 1 MΩ // 20 pF
Time base
  • 50 ns/Div — 1 μs/Div: Equivalent Time Mode
  • 2 μs/Div — 200 μs/Div: Extended Real Time Mode
  • 500 μs/Div — 50 ms/Div: Real Time Mode
  • 100 ms/Div — 20 s/Div and External: Roll Mode
External clock < 10 kHz
Memory 2 × 455 cells (alternating) analog / 1024 words digital
Features
  • 2 channels
  • 6 memory banks
  • 2 cursors
Weight 3.9 kg (8.5 lb)

Internals

The 7D20 uses an analog shift register (CCD) for high-speed signal acquisition, and then digitizes the stored analog signal at a lower speed (see Patent US 4527117A). This design allowed the 7D20 to capture single-shot events at 40 MSamples/s even though this exceeded the speed of ADCs of the time. A microprocessor (68B09) in the plug-in controls most of its functions.

The analog waveforms that are sent to the 7000-series mainframe are generated by vertical and horizontal DACs. The DACs outputs can be calibrated for scaling and shift so that signals are accurately displayed on the oscilloscope screen.

The 7D20 has a "roll" mode that emulates a paper roll chart, as if the waveform were being drawn by a pen on the right side of the screen while the paper is being moved to the left at a constant rate. No equivalent to "roll" exists in analog scopes. The Tektronix 2212/2216, 2220/2221/2230 and possibly others also have this feature.

The 7D20 can give NVRAM errors that are often easy to fix.

Links

Pictures

  • 7D20 picture from manual

    7D20 picture from manual

  • 7D20 picture in 7603 mainframe, from manual

    7D20 picture in 7603 mainframe, from manual

Parts

Some Parts Used in the 7D20

Part Part Number(s) Class Description Used in
155-0196-00 155-0196-00 Monolithic integrated circuit trigger 455 • 7D20
155-0217-00 155-0216-00 • 155-0217-00 Monolithic integrated circuit variable-gain transconductance amplifier 335 • 475 • 7D20 • FG504
2N3958 151-1054-00 • 151-1054-01 • 151-1054-02 Discrete component dual n-channel JFET FG503 • MR501 • M3 • PG505 • SC501 • SC502 • SC503 • SG502 • 1450 • 1501 • 1502 • 1503 • 221 • 5A23N • 5CT1N • 577 • 603 • 603A • 604 • 604A • 605 • 606 • 606A • 606B • 607 • 607A • 620 • 624 • 7CT1N • 7D15 • 7D20 • 851
Motorola 6809 156-1494-00 • 156-1494-01 Monolithic integrated circuit 8-bit microprocessor 2424L • 2440 • 7D20 • DM5120 • DM5520 • Keithley 193A • Keithley 196 • Keithley 199
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