| 摘要 |
<p>A microwave transmitter (10) comprises a signal modulator (12) 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 (18) responsive to the microwave frequency signal produces an amplified output signal suitable for transmission to a remote location. The signal modulator (12) and the amplifier (18) have upper power limits which are sufficiently below their respective two-tone third order intermodulation intercept points that each has a carrier-to-triple-beat power ratio at least equal to first predetermined values. The gain of the amplifier (18) is high enough that, notwithstanding the power limitation imposed on the amplitude modulated signal by virtue of the upper power limit of the signal modulator (12), 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 a desired carrier-to-noise ratio and by thermal noise. </p> |
