S-4: Difference between revisions

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(New page: The S4 sampling plug-in head provides one 50-ohm SMA port with a 25ps risetime. The S4 provides a trigger pickoff signal for internal triggering and is specified for less than 5mV of noise...)
 
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The S4 sampling plug-in head provides one 50-ohm SMA port with a 25ps risetime. The S4 provides a trigger pickoff signal for internal triggering and is specified for less than 5mV of noise.
{{Plugin Sidebar
|manufacturer=Tektronix
|series=7000 and 3S series sampling heads
|type=S-4
|summary=Sampling Head
|image=Tek-s-4.jpg
|caption=S-4 head
|introduced=1968
|discontinued=1990
|designers=George Frye
|manuals=
* [[Media:070-0896-01.pdf|Tektronix S-4 Instruction Manual, Revised OCT 1986]] (OCR)
* [[Media:070-0896-00.pdf|Tektronix S-4 Manual 1969]]
* [http://w140.com/tek_S4_1985.pdf Tektronix S-4 Manual, revised 1985]
* [http://w140.com/frye_s4_gate.pdf George Frye's Explanation of S-4 sampler in October 1968 Service Scope]
* [[Media:Tek s-4 fcp april 1969 - OCR.pdf|Tektronix S-4 Factory Calibration Procedure, April 1969]] (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.
 
{{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.
 
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.
 
==Prices==
1979: $1,435 (~$5,600 in 2022 Dollars)
 
According to an [[Media:Tek Schottky Diodes Memo rot.pdf|internal memo]], in 1979 annual sales were estimated at 150 units.
 
==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>
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>
 
 
[[Category:7000 and 3S series sampling heads]]

Revision as of 10:40, 14 October 2022

Manuals – Specifications – Links – Pictures

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
  • trigger signal pick-off for internal triggering

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.

Prices

1979: $1,435 (~$5,600 in 2022 Dollars)

According to an internal memo, in 1979 annual sales were estimated at 150 units.

Links

Pictures