TekWiki

7J20: Difference between revisions

Page Discussion Repairs

7J20 (view source)

Revision as of 14:45, 3 March 2023

4,658 bytes added ,  3 March 2023
no edit summary
No edit summary
No edit summary
(41 intermediate revisions by 5 users not shown)
Line 1: Line 1:
The Tektronix 7J20 is an optical spectrometer for the 250nm to 1100nm region.
{{Plugin Sidebar
It is a "rapid scan" spectrometer, which means that it can capture the spectrum
|manufacturer=Tektronix
quickly. It can show how the spectrum of an optical input changes at temporal resolution of a few milliseconds.
|series=7000-series scopes
The 7J20 is based on a [http://en.wikipedia.org/wiki/Monochromator#Czerny-Turner_monochromator Czerny-Turner Monochromator].
|type=7J20
|summary=Optical Spectrometer
|image=Tek7J20.jpg
|caption=Tektronix 7J20 in [[7633]] mainframe
|introduced=1975
|discontinued=1976
|manuals=
* [[Media:70-1642-00.pdf|Tektronix J20/7J20 Service Manual]]
* [[Media:70-1641-00.pdf|Tektronix J20/7J20 Operators Manual]]
* [[Media:Tek 7j20 interim service manual.pdf|Tektronix J20/7J20 Interim Service Manual]]
* [[Media:070-1743-00.pdf|Tektronix 016-1000-00 RSS External Normalizer Manual]]
* [[Media:TEK RSS Brochure.pdf|Tektronix J20/7J20 Brochure]]
* [[Media:RSS Applications.pdf|Tektronix J20/7J20 Application Notes 9 & 11]]
* [[Media:RSS R&D Article 11-1974.pdf|R/D Article - November 1974]]
* [https://w140.com/tek_7J20_from_1975_cat.pdf Section in 1975 Catalog in 7J20]
* [[Media:TEK 7J20 Advertisement 06-1975.pdf|Tektronix J20/7J20 Advertisement - June 1975]]
* [[Media:Jere marrs rapid-scanning spectrometry.pdf|Jere Marrs, "Rapid-Scanning Spectrometry"]]
* [[Media:Peter burke fast-scan spectrometry.pdf|Peter Burke "Fast-Scan Spectrometry"]]
}}
The '''Tektronix 7J20''', which only appears in the 1975 catalog, is a "rapid scan" optical spectrometer for the 250 nm to 1100 nm region. ''Rapid scan'' means that it can capture the spectrum quickly enough to show spectral changes at temporal resolution of a few milliseconds.


* [http://w140.com/tek_7J20_from_1975_cat.pdf Section in 1975 Catalog in 7J20 (PDF)]
The spectrometer is packaged in two enclosures linked by an umbilical cable.
The 7J20 is a 2-wide plug-in for [[7000-series scopes]] containing the sweep timing and mainframe interface circuits.
The external enclosure is labeled "J20".
It has controls for the optical components (grating, filters etc.) on one side and an input aperture on the other.
 
{{BeginSpecs}}
{{Spec | Spectral range | 250 nm to 1100 nm }}
{{Spec | Resolution |
* Grating A: ≤4 nm in a 400 nm span (selectable 300-700, 400-800, 500-900, 600-1000, or 700-1100 nm
* Grating B: ≤0.4 nm in a 40 nm span continuously variable through the spectral range }}
{{Spec | Slit | 10 to 5000 μm wide (1-2-5 sequence), 10 mm high }}
{{Spec | Filters | ND1, ND 2, 500 nm monopass, 800 nm monopass, UV block (≤400 nm), UV pass (250-330 nm), open (no filter) }}
{{Spec | Scan | 10 or 20 ms base sweep, 50 to 1000 ms (1–2–5) settings run successive 20 ms sweeps up to the selected integration time }}
{{Spec | Display span | Grating A, 40, 20, 10 or 4 nm/Div ; Grating B, 4, 2, 1 or 0.4 nm/Div }}
{{EndSpecs}}
 
==Price==
$12,000 in 1975 (~$61,000 in 2021 dollars)
 
==Links==
* [https://youtube.com/watch?v=7zR4Os6JEac 7J20 in operation @ VintageTek Museum] (YouTube)
 
==Internals==
The instrument is based on a [[wikipedia:Monochromator|Czerny-Turner Monochromator]], in essence a narrow slit followed by a [[wikipedia:Diffraction grating|diffraction grating]].
A [[wikipedia:Vidicon|vidicon tube]] scans the optical spectrum and produces a periodic electric signal which is then displayed by the scope mainframe.
[[File:7J20-principle.jpg | thumb | 400px | center | Operating principle (click to enlarge) ]]
 
The internal vidicon horizontal scan voltage corresponds to wavelength, but not in a linear way.
To provide a linear nm/div horizontal display on the 7000-series mainframe, the vidicon horizontal scan signal is passed through a function generator IC, the [[155-0106-00]] (U1550 and U1590), which implements an interpolated lookup table.
Inside the J20, there are 40 trimmer potentiometers that allow the lookup function to be tweaked so that the horizontal scale of the system is accurate.
[[File:Tek_j20_interim_normalizer2.png | thumb | 400px | center | Normalizer (click to enlarge) ]]
 
The 7J20 is very rare. According to Dennis Tillman, ''Best estimate is ~40 were actually built.''
 
==Pictures==


<gallery>
<gallery>
File:Tek7J20.jpg
Tek7J20.jpg           | 7J20 (plug-in part) in [[7633]] mainframe
7J20_complete.jpg      | 7J20 plug-in part and J20 spectrometer connected (catalog picture)
7J20_from_1975_cat.jpg | 7J20 with J20 in measurement setup (1975 catalog picture)
P7001-7J20.jpg        | 7J20 with J20 in [[P7001|7704A/P7001]](1975 catalog picture)
Tek j20 internal 1.jpg|J20
Tek j20 internal 2.jpg|J20
Tek j20 internal 3.jpg|J20
Tek j20 internal 4.jpg|J20
Tek j20 internal 5.jpg|J20
Tek j20 internal 6.jpg|J20
Tek j20 front 1.jpg|J20
Tek 7j20 1.jpg|7J20
Tek 7j20 2.jpg|7J20
Tek 7j20 3.jpg|7J20
Tek 7j20 4.jpg|7J20
Tek 7j20 5.jpg|7J20
Tek 7j20 6.jpg|7J20
Tektronix-J20 UV Fiber Optic Sensor-Full-lores.JPG | J20 UV Fiber Optic Sensor
Tektronix-J20 UV Fiber Optic Sensor-Head-lores.JPG | J20 UV Fiber Optic Sensor Head
Tektronix-J20 UV Fiber Optic Sensor-Slit-lores.JPG | J20 UV Fiber Optic Sensor Slit
Tektronix-J20 Ring Adapter-Face-hires.JPG  | J20 Mounting Ring Adapter Face
Tektronix-J20 UV Fiber Optic Sensor-Ring Adpapter-Back-hires.JPG |J20 Mounting Ring Adapter Back
Tektronix-J20 UV Fiber Optic Sensor-Ring Adpater-Side-hires.JPG |J20 Mounting Ring Adapter Side
</gallery>
</gallery>
{{Custom ICs|7J20}}
{{Custom ICs|J20}}
[[Category:7000 series combined plugins]]
[[Category:7000 series special-function plugins]]
[[Category:Spectrum analyzers]]
[[Category:Optoelectronic instruments]]
[[Category:Specifications needed]]
Retrieved from "https://w140.com/tekwiki/wiki/Special:MobileDiff/8587...80454"