Type N is a complete sampling subsystem, using the 500-series oscilloscope just as a power supply and a display. The oscilloscope is operated in X-Y mode and gets its horizontal signal from the Type N plug-in instead of from the scope's sweep circuitry. The input signal is applied through a 50 Ω GR-874 connector.
The sampling circuit of the Type N is primitive. It uses a single diode, the "interrogate diode", D5480. The strobe pulse is added to the input signal using a passive summing circuit. Consequently, the amplitude of the kick-out pulse from the input is high, about 150 mV.
The vertical scale of the Type N is fixed at 10 mV/cm, making Type N one of the few Tektronix plug-ins with fixed vertical gain. In practice, attenuators such as the 017-011 can be placed in the signal path, external to the Type N, to achieve the desired sensitivity. Using an input attenuator also has the effect of attenuating the kick-out pulse seen by the device under test.
According to Stefan Graef (http://www.messmuseum.de/tek661.htm),
The engineer behind the N was Norm Winningstad. He worked at Hughes Aircraft Electronics Division and was offered a job at HP's oscilloscope division to join their Sampling Scope team. After getting informed about the work he went to Tektronix developing the N (according to: "A narrative history of Hewlett-Packard from 1939-1990" by John Minck)
For calibration of the timebase of the Type N, the 013-028 Timing Standard was produced.
- Rise time: 600 ps (Bandwidth ~580 MHz)
- Deflection: 10 mV/Div (fixed)