| 摘要 |
PURPOSE:To check automatically the service area in a receiver by sending a synchronizing data signal from a transmitter at each prescribed time in a pocket pager system and allowing a receiver to display the abnormality state when the signal is not received. CONSTITUTION:A timing signal generating section 14 of a transmitter generates a timing pulse signal (a) with a period of T1 sec. Every time a counter section 18 counts the timing signal (a) for 15 times, a control section 13 outputs a control signal (b). A synchronizing data generating section 12 generates a synchronizing data signal (d) at each T2 sec when the control signal (b) is received and irradiates a synchronizing data signal (d) from a transmission antenna 15 through a high frequency transmission section 16 as a radio wave for T4 sec. A control section 29 of a receiver receiving a synchronizing data signal (g) from a reception data analysis section allows a timing signal generating section to generate a timing signal (e). A switching drive signal (f) is controlled to a low level by the timing signal (e) and when no synchronizing data signal (g) is received during T5 sec while a power switching section 26 is in the closing state, the control section 29 discriminates it as the abnormal state and makes an abnormity display section 30 output an abnormality display signal (j). |
