WT4 Millimeter Waveguide System: Regenerative Repeaters

Regenerative Repeaters By C. E. BARNES, P. BROSTRUP-JENSEN, E. T. HARKLESS, R. W. MUISE, and A. J. NARDI (Manuscript received April 7, 1977) The electronic circuitry and physical structure of 12 two-phase repeaters made for use in a field evaluation test are described. The repeaters consist of four kinds of circuitry; millimeter-wave circuits covering the 40 to 110 GHz range, IF circuits at 1.2 to 1.6 GHz, pulse circuits for the 274 Mb/sec pulse stream, and power supply circuits. All repeaters have been successfully operated over the trial repeater link in northern New Jersey. The results of this repeater development effort are the basis for an estimate of the performance obtainable in future four-phase repeater performance. This estimate has been used in the system repeater spacing calculations. I. INTRODUCTION A repeater design has been developed for the WT4 system which can regenerate a 274 megabit per second binary phase-modulated bit stream on mm-wave carriers in the 40 to 110 GHz range. These repeaters have sufficient gain to provide repeater spacing well in excess of the 45 km objective at an error rate of 1 in 109 bits when used with the transmission medium described in this issue of the B.S.T.J. This error rate is attained with a signal to noise ratio which is only a few decibels above the theoretical minimum. Twelve field evaluation test models have been constructed with three models each near 40, 54, 80, and 108 GHz. The models all have identical IF, baseband, and power supply circuitry, but differ in the construction and tuning of the frequency-sensitive millimeter-wave and equalizer circuits.