A new frequency agile transmitter combining system for North American cellular

Abstract

A totally passive yet frequency-agile transmitter combining system is described, which allows each site transmitter to shift to any of the frequencies within its frequency windows, thus allowing instantaneous selection of any of the 416 frequencies within a 12.5-MHz frequency allocation. The system is described and compared with available alternatives with respect to frequency agility, selectivity, DC to RF efficiency, intermodulation rejection, space utilization, and initial cost. Field testing in a nonwireline system in Portland, OR, USA is described, and the adaptability of the system to present and future frequency planning is discussed.<>