JPS5454073A - Outside signal detector for electronic watch - Google Patents

Abstract

PURPOSE:To detect the external signals without the use of any special device other than the mechanism of an electronic watch and without stopping the watch by opening the both ends of a coil, which is operative to drive a converter while there is not normal drive signal in the converter. CONSTITUTION:An input 8 is such a signal as takes a level H for the pulse width for driving a converter each unit time thereof. This signal is alternately produced by a reverse pulse circuit 1. When the input signal 8 is at a high level H, i.e., in case the converter is driven1 a NAND gate 2 acts as a NOT, and buffers 4 and 5 are supplied with a gate input of the same phase so that the output of the circuit 1 is fed to the coil of the converter. When, on the contrary, the input signal 8 is at a low level L, the NAND gate 2 is closed to generate an output at the level H. As a result, the gate of the transistor 4 is at the level H whereas the gate of the transistor 5 is at the level L so that the coil of the converter is brought into an open condition. If, at this time, there is any magnetically modulated input from the outside, a voltage is established between the both terminals of the coil 6 and can be detected by a detecting circuit 7.