4S2 Pulser
The Tektronix 4S2 Pulser is a portable fixture used for field texting of the 4S2 dual-channel sampling plug-in (for the 661 scope).
It is run off a pair of 22.5 V batteries. A 100 kHz oscillator built with a 2N964 transistor drives a 100 mA, 6 pF tunnel diode. The output signal is delayed by 30 ns through a length of RG-174 cable to allow for pre-triggering.
The 4S2 is supposed to display a rise time of no more than 105 ps using this pulser.