The Tektronix 067-1338-0x is a calibration step generator for SD-series sampling heads. Suffix -00 to -06 models differ only by the power cord type.
The output pulse is a positive-going step of approximately 250 millivolts. The rise time is specified on a per-unit basis. The maximum risetime for a 067-1338-00 is 19.5ps.
Output is generated in a head that attaches directly to the DUT via an 3.5_mm_connector.