| 摘要 |
PROBLEM TO BE SOLVED: To obtain the comparatively simple and inexpensive non-regenerative relay alarm monitor system in which an alarm monitor MODEM panel or the like is required for frequencies between frequency bands by adopting a configuration where a squelch function is utilized so as to output a modulation wave with a comparatively low transmission capability thereby monitoring an alarm. SOLUTION: A reception radio frequency conversion panel (reception RFC) 1 converts a reception signal into an intermediate frequency signal, a distribution circuit 2 distributes the intermediate frequency signal into two, the one is fed to a changeover circuit 8 and the other is fed to a squelch discrimination circuit(SDC) 5. When the reception signal satisfies a squelch condition, the SDC 5 provides an output of logic 'H' to an OR circuit 7 and an alarm monitor modulation panel (AWM) 6. When an output of the OR circuit 7 is logical H, the changeover circuit 3 provides an output from the changeover circuit 2 and when an output of the OR circuit 7 is logical L, the changeover circuit 3 provides an output from the AWM 6 to a transmission RFC4. The AWM 6 modulates with the same frequency as the intermediate frequency a signal from the SDC 5 and an alarm from the reception RFC1 and provides an output of the result. Thus, the comparatively simple and inexpensive non-regenerative relay station is realized. |
