WT4 Millimeter Waveguide System: Field Evaluation Test System Performance

The WT4 waveguide transmission system is a long-haul, high-capacity digital transmission system. The system frequency multiplexes 124 high-frequency carriers into the band 40-110 GHz with each carrier phase-modulated by a 274-Mbaud digital bit stream. 1 A field evaluation test was carried out in order to obtain a measure of the overall system performance of the WT4 waveguide transmission system. This test included all the elements of a complete operating system such as protection switching, span terminating, fault locating, auxiliary communications, and maintenance, in addition to 12 operating 2147 repeaters, channelizing networks, and 14 km of field-installed waveguide. In this paper the emphasis will be placed on the combined performance of the repeaters, line equalizers, channelizing networks, and the waveguide medium. Companion papers 2-5 discuss the design of each of these individual elements in detail. Similarly, the span terminating, protection switching, auxiliary communications, and maintenance subsystems are discussed in an additional companion paper.6 For the field evaluation test, 14 km of waveguide was installed from a metropolitan junction station at Netcong, New Jersey, to a temporary equipment shelter at Long Valley, New Jersey. At each end of the waveguide a complete band diplexer array was installed along with enough channel diplexers to allow the testing of the 12 repeaters that were built for the field evaluation test.* The repeaters were divided into four groups, each of three repeaters centered near 40, 55, 80, and 110 GHz.