Synchronizable clock with a mechanical resonator as regulator, especially receiver clocks synchronized by wireless signals and synchronous clocks driven by alternating current having a mechanical regulator forming a principal part of a running reserve. A coupling is provided between the resonator and the hand mechanism, which only transmits one half of the counting impulses. There is also a regulating mechanism which is connectable to the resonator and which alters the spring force in the resonator according to intensity and position in proportion to the oscillating masses in such a manner that a reversal of the motion of the oscillating masses occurs in the region of the normal dead center.
A highly accurate watch, comprising a quartz crystal time base and a movement controlled by an oscillator regulated to run slightly fast and being periodically connected to the quartz crystal time base. In one embodiment, a pulse counter totals the number of pulses put out by the watch oscillator during its normal operation and activates means to stop the oscillator when a sufficient number of pulses equal to a fixed time period has been reached. A second counter totals the pulses from the quartz cyrstal time reference and reactivates the watch when the number pulses equals the fixed time period thereby wiping out accumulated time errors. In a second embodiment, the output from a balance wheel oscillator and a divided down time base frequency are fed to a flip-flop. The output square wave increases in width due to the frequency difference between the balance wheel and time base and is integrated by an RC circuit. A Schmitt trigger circuit and monostable multivibrator are coupled to the flip-flop. so that the trigger circuit is activated for a fixed short time interval and stops the balance wheel through a solenoid. After elapse of the fixed time interval, the balance wheel starts again.
