| 摘要 |
PURPOSE:To eliminate a frequency converting part to simplify the constitution of circuit and to perform the modulation with a digital signal, by providing a PLL circuit to a microwave modulating circuit and supplying the digital signal of a microwave band directly to a VCO. CONSTITUTION:A frequency synthesizer of PLL constitution is added to a microwave modulating circuit, and a data signal 10 is fed directly to a voltage control oscillating part 21 of the PLL circuit. The signal of a microwave band sent from the part 21 is branched by a power distributing part 22, and one of the branched two signals is amplified by a power amplifier 26 to be fed to an antenna part through a terminal 16. The other output given from the part 22 is applied to a PLL circuit part 24 to receive a phase wave detection with the output given from a reference crystal oscillating part 25. The control signal sent from the part 24 is fed back to the part 21. Then the frequency of the synthesizer is controlled at the control circuit part 25. Thus a frequency converting part is eliminated to simplify the circuit constitution. Then the modulation is possible with a digital signal. |
