MICROWAVE COMMUNICATIONS SYSTEM

摘要

A microwave transmitter comprises a signal modulator for receiving an input signal that includes up to 75 video and audio channels and producing an amplitude modulated signal in the microwave frequency range corresponding thereto. An amplifier responsive to the microwave frequency signal produces an amplified output signal suitable for transmission to a remote location. The signal modulator and the amplifier have upper power limits which are sufficiently below their respective two-tone third order intermodulation intercept points that the carrier-to-triple-beat power ratios of each are respectively at least equal to first predetermined values. The gain of the amplifier is high enough that, notwithstanding the power limitation imposed on the microwave frequency signal by virtue of the upper power limit of the signal modulating means, the power of the amplified output signal is at least equal to a second predetermined value. The sum of the gain and the noise figure of the transmitter measured in decibels has an upper limit determined by the desired carrier-to-noise ratio and by thermal noise.