Experimental Verification of the Error-Rate Performance of Two Types of Regenerative Repeaters for Differentially Coherent Phase-Shift-Keyed Signals

High-speed long-haul communication by means of millimeter waves transmitted in the circular electric mode through a multimode circular waveguide was described by S. E. Miller 1 in 1954, and subsequently considered in some detail by Rowe and Warters. 2 This paper describes two experimental models of the IF portion of a repeater for such a system and compares their performance with theoretical predictions of error rate. These models could serve equally well as IF sections of repeaters for optical communication systems or microwave radio systems. No attempt is made in these models to equalize the delay distortion of the medium, and no allowance is made for degradation from up converters, down converters, and millimeter-wave circuitry. 1173 1174 T H E BELL SYSTEM TECHNICAL JOURNAL, J U L Y - A U G U S T 1967 Both experimental model repeaters operated at a bit rate of 160 Mb/s and used an IF of 11.2 GHz. The bit rate and the IF were arbitrary choices made for convenience. In an actual system, a somewhat lower IF would be chosen to facilitate building solid-state amplifiers and a somewhat higher bit rate would probably be desirable. Since these model repeaters were to serve as prototypes for an even higher bit rate repeater, no components were used which did not seem capable of being modified to operate up to about twice this bit rate. Section II discusses briefly the two particular choices of modulation scheme which were used, and describes some of the features common to both models.