S-4: Difference between revisions

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{{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 port)}}
{{Spec | Input impedance | 50 Ω (terminated [[SMA connector]])}}
{{Spec | Input range | operating, 1 V<sub>p-p</sub>; max. safe overload, ±5 V }}
{{Spec | Input range | operating, 1 V<sub>p-p</sub>; max. safe overload, ±5 V }}
{{Spec | Noise | < 5 mV}}
{{Spec | Noise | < 5 mV}}

Revision as of 08:14, 23 February 2017

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 operating, 1 Vp-p; max. safe overload, ±5 V
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 plyers. 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


Pictures