PURPOSE: To make possible invariably stable frequency discrimination while facilitating the application to electronic wrist watch or the like to meet the requirement of IC designing by composing the frequency discrimination means of a time announcing signal of a logic circuit.
CONSTITUTION: The counting of a time of a counting circuit 1 is fed to a display 6 through a driver 5. Detected with a receiver 7, the time announcing signal is made binary with a wave height discriminating circuit 9. When the specified frequency is continuously obtained from the outputs, a frequency discriminating circuit 10 outputs continuous "H" signal to a time announcement pattern discriminating circuit 11, which outputs the pulse to actuate a reset-to-zero circuit 12 when the normal time announcement pattern is discriminated. This resets the second counter of a counter 4 while controlling the driver 5 to correct the contents of the indication. The circuit 10 is composed of FF and a logic circuit such as gate.
YOSHIDA JIYUNICHI
KAMIYA KENJI
YAMANO SHIYOUZOU
