A Tunnel Diode Time Mark Generator

A recycling time mark generator has been developed in which the only active element is a shunt connected tunnel diode. The diode is mounted at the junction of a 50/g=W/ stripline T. Two legs of the T are joined with a length of coaxial cable; the third leg proceeds 2.5 cms to a five port mis-match. The mis-match provides five input-output ports, and its distance from the diode determines the pulse width. Pulse width is about 0.8 ns and recycling periods as short as 3 ns and as long as 160 ns have been used. With a selected diode, up to two hundred pulses can be simultaneously recirculated in a 160 ns RG-8 transmission line indefinitely. Short term instability of circulation period as measured by beating the radiated signal with a quartz crystal is less than .05 ps. Bias coefficient of circulation period is 8 ps per mv at 90 mv with a General Electric TD-103 diode, and the tuning range which can be obtained by varying bias is 150 ps. The temperature coefficient of circulation period is 1.5 ps per °C. These measurements were made with a circulation period of 100 ns.