GB1338776A - Automatic time control circuit - Google Patents

Abstract

1338776 Automatic phase control systems; monostable circuits INTERNATIONAL STANDARD ELECTRIC CORP 19 April 1971 [10 March 1970] 23037/71 Headings H3A and H3T An automatic time control circuit for delaying a signal by a predetermined amount includes an adjustable delay circuit 3, a circuit 4 for deriving a control signal pulse C having a length equal to the actual delay suffered by an input pulse A in its passage through a processing circuit 1, 3, 2, a circuit 6, 7 for generating synchronously with the control pulse C a reference pulse D having a duration equal to a predetermined delay, a phase comparator 5 for comparing the control and reference pulses for controlling the delay provided by 3. The pulse D is obtained by a circuit 7 counting a predetermined number of reference pulses from oscillator 6 when initiated by the control pulse C. The adjustable delay circuit is a monostable circuit (see Fig. 4) whose time constant is varied by the phase comparator 5 output. A monostable circuit such as shown in Fig. 4 has its unstable period varied by the application of a control voltage CV to a voltage controlled resistor R which may be an F.E.T. or to vary bias voltages V 1 or V 2 for controlling the discharge time of C. The circuit produces an output pulse of controlled width at B<SP>1</SP> in response to an input pulse at A<SP>1</SP>.