| 摘要 |
PURPOSE: A system and a method for transmitting and receiving a high frequency wave for an automatic meter reader are provided to simplify a circuit thereof and to reduce the manufacturing cost by utilizing only one PLL IC, VCO and PLL filter. CONSTITUTION: A system for transmitting and receiving a high frequency wave for an automatic meter reader includes a RF module for receiving RF signal through an antenna and for outputting the RF signal by demodulating the RF signal into AF signal and a control module for communicating the AF signal with the RF module and for controlling the RF module. The RF module includes a RF input and output block, a RF part, an IF part, an AF input part, a PLL circuit and a power amplifying block. The control module includes a power switch for supplying a power to the receiving block during the reception mode and a CPU for outputting a PLL circuit control signal and a power switch control signal. In the RF module, The RF part in the RF module includes a RF filter(12) and a low noise amplifier(13) connected to the RF filter(12) for amplifying the filtered RF signal.
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