| 摘要 |
PURPOSE:To prolong the continuous operating time of the receiver by suppressing power consumption at carrier sensing of the receiver. CONSTITUTION:A timer circuit 7 drives a control circuit 9 for each specified time and a power supply circuit 11 supplies power intermittently to a radio wave detection section 5. While the radio wave detection section is in operation, a received radio wave voltage is amplified by a high frequency amplifier circuit 15 and detected by a detection circuit 19 via a changeover circuit 17. When no radio wave is in existence, the radio wave detection section is intermittently in operation. When the detection circuit detects an object radio wave, a voltage over a specified voltage is outputted from the detection circuit to the control circuit for a specified time or over and power is supplied to the radio wave detection section and a reception section 13 and an output signal of the changeover circuit is outputted to a mixer circuit 21, in which the signal is converted into an intermediate frequency voltage, it is amplified by an intermediate frequency amplifier circuit 23, converted into a digital signal at a demodulation circuit 25 and a data processing circuit 27 processes data. After a series of data processing is made completed, a data processing end signal is fed to the control circuit and the circuit restores to a radio wave monitor state. |
