S-4: Difference between revisions
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* [http://w140.com/frye_s4_gate.pdf George Frye's Explanation of S-4 sampler in October 1968 Service Scope (PDF)] | * [http://w140.com/frye_s4_gate.pdf George Frye's Explanation of S-4 sampler in October 1968 Service Scope (PDF)] | ||
}} | }} | ||
The '''Tektronix S-4''' is a sampling head for 7000- and 3S-series samplers. | 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}} | {{BeginSpecs}} | ||
{{Spec | Rise time | 25 ps (observed with [[S-50]] or [[S-52]], 35 ps) }} | {{Spec | Rise time | 25 ps (observed with [[S-50]] or [[S-52]], 35 ps) }} | ||
{{Spec | Bandwidth | 14.5 GHz }} | {{Spec | Bandwidth | 14.5 GHz }} | ||
{{Spec | Input impedance | 50 Ω (terminated SMA | {{Spec | Input impedance | 50 Ω (terminated [[SMA connector]])}} | ||
{{Spec | Input range | | {{Spec | Input range | 1 V<sub>p-p</sub> (operating) }} | ||
{{Spec | Maximum input | ±5 V max. non-destructive }} | |||
{{Spec | Noise | < 5 mV}} | {{Spec | Noise | < 5 mV}} | ||
{{Spec | Features | | {{Spec | Features | | ||
| Line 26: | Line 29: | ||
==Internals== | ==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 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. | To disassemble the sampler hybrid, first remove it from the sampler board as per the manual. | ||
connector using a 7/32" wrench and remove the 20 dB attenuator with small | Remove the input connector using a 7/32" wrench and remove the 20 dB attenuator with small pliers. | ||
to the housing using roll pins that can be pressed out with a 0.030" pin punch. | The ceramic board is held to the housing using roll pins that can be pressed out with a 0.030" pin punch. | ||
each about 0.75mm square. | The hybrid has six diodes, each about 0.75mm square. | ||
are wire-bonded (twice) over a gap to the next step in the strobe line. | The cathodes are glued to the gold substrate with conductive epoxy and the anodes | ||
diode may fit across the gap but cleanly removing a failed diode without damaging the substrate would be | are wire-bonded (twice) over a gap to the next step in the strobe line. | ||
quite difficult. | 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== | ==Links== | ||
* [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_special/S4.html S-4 page @ amplifier.cd] | * [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== | ==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 | |||
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]] | [[Category:7000 and 3S series sampling heads]] | ||
Revision as of 23:12, 25 April 2018
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
