By T. M. Straus, R. T. Hsu, and L. A. Kaufman, Hughes Aircraft Company
Recent microwave circuit developments have led to the realization of a third order intercept point of + 62 dBm in a broadband block conversion type 13 GHz solid state transmitter. The 5 dB increased power output that this latest development allows adds to previous CARS band microwave block conversion transmitters, which in total now span a power capability ratio in excess of 200: 1. A summary explanation of the steps culminating in the dual-feedforward circuit utilized in this highest power transmitter is provided. The impact of improved third order intercept on noise and distortion in LDS microwave operation is reviewed. The resultant range capability is examined for various geographical areas. Comparison with fiber optic transportation systems is made and the advantages of CATV architectures employing parallel fiber and microwave paths is explored.