| 摘要 |
PURPOSE:To improve the efficiency of a transmitter, to increase the dynamic range, to improve the S/N and to reduce the radio wave disturbance to other radio equipment by increasing the transmission power of the transmitter in response to the decrease in the reception input level of the receiver at rainfall. CONSTITUTION:If the input signal fo a received radio wave A is decreased remarkably due to rain fall attenuation, the attenuated received radio wave A is received by a transmission/reception antenna 1 and only a desired frequency of 260GHz band is selected by a reception band pass filter 9 through a multiple coupler 2. The signal of 26GHz band formed by the local oscillator 15 and the signal are converted into an intermediate frequency (140MHz) by a reception frequency conversion section 11. Since the voltage of an AGC 13 of an intermediate frequency amplifier section 12 varies with the reception input, the voltage of the AGC 13 is fed back to an automatic transmission power adjusting circuit (APC circuit) 17 to change a bias voltage of a gun diode in the transmission local oscillation section 6, thereby controlling the transmission power.
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