11GHz ALL SOLID STATE RADIO RELAY EQUIPMENT USING GUNN-DIODE OSCILLATORS AND IMPATT-DIODE AMPLIFIER.

An all solid state microwave radio relay equipment has been developed and will be used in NTTPC's (Nippon Telegraph and Telephone Public Corporation) short-haul 11 GHz microwave network. system has been developed using a low-noise Gunn-diode fm-modulator and a high-power reflection type IMPATT-diode stable amplifier for the transmitter, and a cavity-stabilized highly-stable Gunn-diode oscillator with a low-noise Schottky-barrier-diode mixer for the receiver. The equipment has a message capacity of 600 telephone circuits with 5,000 pw noise power per 120 km route distance and utilizes a baseband repeater system in the frequency range of 10. 7 GHz to 11. 7 GHz. Transmitting output power is 350 mw and the receiver noise figure is 9 db. Meantime between failures is approximately 50,000 hrs.