PURPOSE: To improve accuracy for measurement with a simple constitution by forming a reference signal with combining outputs from plural groups of binary storage devices being connected with quartz oscillators in a set resonance frequency.

CONSTITUTION: An output of resonance frequency 2N like 2048Hz etc. in quartz oscillator is sequently demultiplied by FF11W18 etc. forming a binary storage device in a demultiply circuit 1. When the demultiplied outputs from FF12W14 are charged into a NAND circuit 2, the circuit 2 generats a negative pulse having identical pulse width at duty of demultiplied output from FF14 with the demultiplied pulse width from FF12. In same way, the demultiplied outputs from FF15W 18 are treated in OR circuits 5 and 6 in where inverter 8, NAND gates 3 and 4, and pulse a are charged, and a reference signal having 50% duty ratio and the frequency 1000Hz for accurate stop watch is formed by combining demultiplied outputs from FF11W18 with charging outputs from the circuits 5 and 6, and the demultiplied output from FF11 into AND gate 7. With this simple constitution, it enables to improve accuracy for measurement.