S-4: Difference between revisions
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{{Plugin Sidebar 2 | | |||
title=Tektronix S-4 | | |||
summary=Sampling Head | | |||
image=Tek-s-4.jpg | | |||
caption=S-4 head | | |||
series={{3S+7S}} | | |||
introduced=1968 | | |||
discontinued=1990 | | |||
manuals= | |||
* [[Media:070-0896-01.pdf|Tektronix S-4 Instruction Manual, Revised OCT 1986 (OCR, PDF)]] | |||
* [http://w140.com/tek_s4.pdf Tektronix S-4 Manual, copyright 1969 (PDF)] | |||
* [http://w140.com/tek_S4_1985.pdf Tektronix S-4 Manual, revised 1985 (PDF)] | |||
* [http://w140.com/frye_s4_gate.pdf George Frye's Explanation of S-4 sampler in October 1968 Service Scope (PDF)] | |||
* [[Media:Tek s-4 fcp april 1969 - OCR.pdf|Tektronix S-4 Factory Calibration Procedure, April 1969 (PDF, OCR)]] | |||
}} | |||
The '''Tektronix S-4''' is a sampling head for 7000- and 3S-series samplers. | |||
It was designed by [[George Frye]] and [[introduced in 1968]]. | |||
It is the fastest of the S-series plug-in samplers. | |||
The | {{BeginSpecs}} | ||
{{Spec | Rise time | 25 ps (observed with [[S-50]] or [[S-52]], 35 ps) }} | |||
{{Spec | Bandwidth | 14.5 GHz }} | |||
{{Spec | Input impedance | 50 Ω (terminated [[SMA connector]])}} | |||
{{Spec | Input range | 1 V<sub>p-p</sub> (operating) }} | |||
{{Spec | Maximum input | ±5 V max. non-destructive }} | |||
{{Spec | Noise | < 5 mV}} | |||
{{Spec | Features | | |||
* trigger signal pick-off for internal triggering | |||
}} | |||
{{EndSpecs}} | |||
==Internals== | |||
The [[Sampler#Six-Diode_Sampler|S-4 sampling gate]] is based upon a traveling wave trapped-charge transmission line | |||
in which the sampling window is set by the propagation time of a pulse edge through a thick-film transmission line. | |||
This technique requires only a sharp pulse edge rather than a precise pulse width, which is harder to generate. | |||
The sampling diodes are housed in a special coaxial connector that provides a high bandwidth signal path. | The sampling diodes are housed in a special coaxial connector that provides a high bandwidth signal path. | ||
To disassemble the sampler hybrid, first remove it from the sampler board as per the manual. | |||
Remove the input connector using a 7/32" wrench and remove the 20 dB attenuator with small pliers. | |||
The ceramic board is held to the housing using roll pins that can be pressed out with a 0.030" pin punch. | |||
The hybrid has six diodes, each about 0.75mm square. | |||
The cathodes are glued to the gold substrate with conductive epoxy and the anodes | |||
are wire-bonded (twice) over a gap to the next step in the strobe line. | |||
It appears that a standard beam-lead diode may fit across the gap | |||
but cleanly removing a failed diode without damaging the substrate would be quite difficult. | |||
==Links== | |||
* [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_special/S4.html S-4 page @ amplifier.cd] | |||
* [https://kh6htv.files.wordpress.com/2015/11/an-02a-oscopes.pdf James R. Andrews, ''Comparison of Ultra-Fast Rise Sampling Oscilloscopes''. Picosecond Pulse Labs App Note AN-2a, 1989] | |||
==Pictures== | |||
<gallery> | <gallery> | ||
Tek-s-4.jpg | |||
Tek s4.jpg | |||
S4_top.jpg | Top view of the S4 plug-in | |||
S4_left.jpg | Left view | |||
S4_right.jpg |Right view | |||
S4 schem.png | Schematic | |||
Tektronix-S4-sampler-board-strobe.jpg | Sampler board, strobe side | |||
Tektronix-S4-sampler-board-preamp.jpg | Sampler board, preamp side | |||
Tektronix-S4-sampler-board-hybrid.jpg | Sampler board, disassembled with parts orientation | |||
Tektronix-S4-hybrid-internal.jpg | Microphotograph of sampler hybrid | |||
S-4_B15_prototype.JPG | S-4 B-prototype, no difference to standard S-4 | |||
Tek s-4 in 7s11.jpg | S-4 in [[7S11]] | |||
7s11-s4.jpg | S-4 in [[7S11]] | |||
</gallery> | </gallery> | ||
[[Category:7000 and 3S series sampling heads]] |
Revision as of 14:32, 23 February 2021
Template:Plugin Sidebar 2 The Tektronix S-4 is a sampling head for 7000- and 3S-series samplers. It was designed by George Frye and introduced in 1968. It is the fastest of the S-series plug-in samplers.
Key Specifications
Rise time | 25 ps (observed with S-50 or S-52, 35 ps) |
---|---|
Bandwidth | 14.5 GHz |
Input impedance | 50 Ω (terminated SMA connector) |
Input range | 1 Vp-p (operating) |
Maximum input | ±5 V max. non-destructive |
Noise | < 5 mV |
Features |
|
Internals
The S-4 sampling gate is based upon a traveling wave trapped-charge transmission line in which the sampling window is set by the propagation time of a pulse edge through a thick-film transmission line. This technique requires only a sharp pulse edge rather than a precise pulse width, which is harder to generate. The sampling diodes are housed in a special coaxial connector that provides a high bandwidth signal path.
To disassemble the sampler hybrid, first remove it from the sampler board as per the manual. Remove the input connector using a 7/32" wrench and remove the 20 dB attenuator with small pliers. The ceramic board is held to the housing using roll pins that can be pressed out with a 0.030" pin punch. The hybrid has six diodes, each about 0.75mm square. The cathodes are glued to the gold substrate with conductive epoxy and the anodes are wire-bonded (twice) over a gap to the next step in the strobe line. It appears that a standard beam-lead diode may fit across the gap but cleanly removing a failed diode without damaging the substrate would be quite difficult.
Links
- S-4 page @ amplifier.cd
- James R. Andrews, Comparison of Ultra-Fast Rise Sampling Oscilloscopes. Picosecond Pulse Labs App Note AN-2a, 1989