High Data-Rate Multiplexer Development

Abstract

Abstract : The significance of this research and development to the Air Force is that an Electron-Beam-Semiconductor (EBS) digital multiplexer has been developed which has the capability of achieving output data rates exceeding 2 Gbits/sec. Two design approaches are presented for multiplexing multiple input data lines into a single output (parallel-to-serial conversion) with 2 Gbits/sec serial output data rate. The first approach uses a CRT-type electron gun, eight input gates, and one silicon diode target. The second approach uses multiple electron sources, multiple input gates, and a single silicon diode target. A gating system is used to present to the target a 0.5-ns aperture time per electron gun. This approach is much less sensitive to misalignment and power supply and RF input drive instabilities than the first approach. In addition, higher output signal amplitudes and a smaller tube are achieved. Output pulse characteristics demonstrated at 2 Gbits/sec data rate are 5 to 7V pulse amplitude into a 50 ohm load and less than 0.25-ns pulse risetime.