| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an alarm transmitter and its method with a comparatively simple and inexpensive configuration without the need for alarm monitor MO DEM panel or the like. SOLUTION: A distribution circuit 2 branches an intermediate frequency signal from a reception radio frequency conversion panel 1 into two. A changeover circuit 3 receives one branched intermediate frequency signal, a changeover control signal, and an oscillation signal from a voltage controlled oscillator 8, and outputs the one branched intermediate frequency signal or the oscillation signal as a switching signal and a transmission frequency conversion panel 4 applies the switching signal with the intermediate frequency into a radio frequency. A squelch decision circuit 5 inputs the other branched intermediate frequency signal an discriminates whether or not the signal is a desired signal. Furthermore, a D/A converter circuit 6 connected to a voltage controlled oscillator is provided and an output voltage from the D/A converter circuit 6 is changed depending on the kind of each alarm and the carrier frequency is changed to transfer the alarm signal.</p> |
