The Tektronix S-52 is a pulse generator head compatible with S-series sampling units like the 3S2, 7S11, and 7S12. It was designed by Murlan Kaufman. It makes use of US Patent US3612910A, "Triggered Pulse Generator Having Automatic Bias Adjustment".
It puts out a 200 mV pulse into a load of 50 Ω. The pulse has a rise time of 25 ps or less. The output is an SMA connector.
In addition to the main pulse output, the S-52 also produces a pre-trigger pulse 85 ns before the main pulse. The delay is generated with a digital counter, and jitter between the pre-trigger pulse and the main pulse is specified as less than 10 ps. The pre-trigger pulse uses a BSM connector.
|Rise time||< 25 ps|
|Output amplitude||200 mV into 50 Ω (SMA)|
|Pulse Duration||> 350 ns|
|Output impedance||50 Ω «reverse terminated» (i.e. having controlled source impedance)|
|Pre-trigger output||85 ns before main pulse (jitter < 10 ps), +1 V into 50 Ω (BSM)|
The S-52 is similar to the S-50, but the S-50 has twice the pulse amplitude. The reason for this is that the S-52 has a 48 Ω resistor between the output tunnel diode and the output connector providing back termination, while the S-50 has no such resistor. Although the S-52 produces a smaller pulse, its output impedance is much better controlled than that of the S-50, and the output resistor may also provide some limited protection for the output tunnel diode.
The S-52 uses a 156-0048-00 (LM3046) transistor array in the timing board.
S-52 front A-prototype
A-prototype of S-52
A1 Timing board (right)
A3 Trigger board (left)
A2 Tunnel Diode Control board (center)
Tunnel diode mount
Tunnel diode mount, detail
TDR "Self Portrait" — pulse reflected on S-6 "through" path (approx. 120 ps one way)
7S12 displaying the incident pulse from an S-52 (nom. < 25 ps) through an S-6 head (nom. < 30 ps). Displayed rise time ~35 ps confirms spec.
Full pulse pattern of a 7S12/S-52 in real time (top trace) and sampled (bottom trace) shown simultaneously on 7844. 7S12 trace at slowest possible sweep.
S-52 pulse in real time (top trace) and sampled (bottom trace) shown simultaneously on 7844. Approximately equal time scales.
Full pulse pattern of a S-52 (A-prototype) , driven by 3S6 (freerunning)