S-51
The Tektronix Type S-51 is a synchronizing head for sampling oscilloscope systems. From a periodic input signal in the 1GHz to 18GHz range, the S-51 generates trigger pulses which have a fixed time relationship with the input signal.
The S-51 only works with periodic signals. (This is more restrictive than repetitive signals.) By synchronizing an 200MHz oscillator at the front-end of the S-51 with with a subharmonic of the input waveform, the fixed time relationship is established.
The S-51 uses a BSM connector for its trigger outout on the front panel.
