The AR6A Single-Sideband Microwave Radio System: Special Test Equipment

Special Test Equipment By R. I. F E L S B E R G * a n d M. E. S A N D S * (Manuscript received January 22, 1983) This paper describes two specialized test sets designed specifically for A R 6 A tran8mit-receive radio equipment alignment. The scanning intermodulation ( I M ) test set can adjust the transmitter for proper gain shape and optimum predistorter performance. It can also confirm that the transmitter is meeting its IM requirements. The pilot selection test set is used to test the radio intermediate frequency receiver units for proper operation during changing received signal conditions. This test set provides signals to simulate either flat or selective fades and can be used to check the pilot resupply function or space-diversity switch transition levels. I. I N T R O D U C T I O N It was realized early in the development of the AR6A f Radio System that special test equipment would be needed to ensure that performance objectives of this new single-sideband (SSB)* system were met. Two specialized test sets have been designed for this purpose: (1) the scanning intermodulation (IM) test set, and (2) the pilot selection test set. Both sets are self-contained in carrying cases with handles and * Bell Laboratories. t Amplitude Modulation Radio at 6 GHz for the initial (A) version. * Acronyms and abbreviations used in the text and figures of this paper are defined at the back of the Journal. 1983, American Telephone & Telegraph Company. Photo reproduction for noncommercial use is permitted without payment of royalty provided that each reproduction is done without alteration and that the Journal reference and copyright notice are included on the first page.