Phase synchronizer

Circuitry for obtaining a signal which is phase synchronized with respect to another signal which has passed through a transmission system after originating at a signal source, said circuitry comprising

• said transmission system wherein the phase of said another signal indeterminately fluctuates due to the transmission system characteristics or the environment thereof;
• a variable phase shifter responsive to the output signal of said signal source for shifting the phase thereof in response to a control signal applied thereto;
• a phase comparator responsive to the signal which has passed through the transmission system and the output signal of the variable phase shifter to provide an output signal indicative of the phase difference between the two signals applied thereto;
• and
• a low-pass filter responsive to said phase comparator output signal to provide said control signal for the variable phase shifter so that the phase of the output signal of the variable phase shifter follows the phase of the transmission system output signal.