PURPOSE: To improve rectification efficiency and to improve signal detection sensitivity by applying an input AC voltage signal with full-wave rectification in a signal detecting circuit which rectifies the AC voltage signal and makes a comparison with a reference voltage.
CONSTITUTION: The input signal 110 is inputted to the 1st rectifier composed of a transistor (TR) 114 through an input buffer circuit 137. On the other hand, a polarity-inverted signal 122 which is inverted by an inverter 112 is inputted to the 2nd rectifier composed of a TR116. A signal appearing on a signal line 121 is the signal obtained by rectifying the AC voltage signal on an output line 111 on full-wave basis. This signal is converted into a DC voltage, which is compared with the voltage of a specific comparison power source 131 by a comparator 132 to obtain a signal detection output 133.
YAMAMOTO KAZUNARI
KATAOKA MUTSUO
IWATA ATSUSHI
NIPPON TELEGRAPH & TELEPHONE
| JPS54100654A | 1979-08-08 |