S-4
The S-4 was designed by George Frye and introduced in 1968. It is the fastest of the S-series plug-in samplers. (An interesting comparison of different sampling heads is found in "AN-3042a, Revision 1, 2/89".)
The S4 sampling gate is based upon a traveling wave trapped-charge transmission line in which the sampling window is set by the propagation time of 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.
Specifications
- Rise time: 25 ps
- Bandwidth: 14.5 GHz
- Input impedance: 50 Ω (SMA port)
- Noise: < 5 mV
- Provides a trigger pickoff signal for internal triggering
Pictures
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Top view of the S4 plug-in
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Left view
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Right view
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Schematic
