Synchronizing pulse comparator circuitry

Abstract

Abstract A circuit for comparing two trains of synchronizing pulses is disclosed wherein the circuitry determines whether the time displacement between the trains is within a predetermined limit, the limit being adjustable. The above circuit comprises a comparator to which is applied the two pulse trains. The output of the comparator is a pulse whose width is a direct function of the displacement. This pulse is applied to an invertor and a monostable multivibrator, the pulse width of which is adjustable. The monostable multivibrator output and the invertor output are applied to a bistable multivibrator. The positive-going, leading edge of the monostable multivibrator output sets the bistable multivibrator and the positive-going, trailing edge of the invertor output pulse resets the bistable multivibrator. The output pulses of the monostable and bistable multivibrator are applied to a second comparator which generates an output alarm signal whenever the bistable multivibrator output signal is greater in time duration than the monostable multivibrator output signal. The occurence of an alarm signal at the output of the second comparator indicates that the time displacement between the pulse trains is greater than the predetermined limit established by the adjustable pulse width of the monostable multivibrator output signal. The second comparator output signal is applied to a second monostable multivibrator which detects the occurrence of an output signal from the second comparator even though the width pulse thereof is very slight. The second monostable multivibrator output signal is then applied to an integrator which provides an output signal only after a predetermined number of pulses of the two trains are out of synchronization. The integrator output signal is then applied to an appropriate control device.

Inventors

• 👤 Ole Skrydstrup
• 👤 Bjorn Larsen

Bibliographic Details