Browse Prior Art Database

Variable Clock With Analog Period Memory

IP.com Disclosure Number: IPCOM000075999D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Burke, MJ: AUTHOR

Abstract

This circuit provides timing pulses for reading punched cards under the condition that successive cards may enter the read station at different speeds. The clocking circuit, as shown, has a variable period with the period being controlled by speed of individual cards.

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Variable Clock With Analog Period Memory

This circuit provides timing pulses for reading punched cards under the condition that successive cards may enter the read station at different speeds. The clocking circuit, as shown, has a variable period with the period being controlled by speed of individual cards.

Pulses P1 and P2 represent the time delay between successive cards. The clock will continue to operate at that period until the period is reset. Two integrators (int A and int B) are provided such that with a voltage input V1, the output increases linearly at a fixed rate. When the input is V2 the output decreases linearly at the same rate. A reset input on the integrator is also provided, which causes the output to be set to a reference voltage (Vref).

At t0 (the rise of P1), int A, starting at Vref, increases until t1 (the rise of P2). At t1, int A starts falling and int R, starting at Vref,. starts increasing. When int A reaches Vref, it starts increasing again and int B starts decreasing. Now when int B reaches Vref, it starts increasing and int A starts decreasing. This cycle pattern continues until the period is again set. The period of the clock is determined by the voltage which the int A output reaches between t0 and t1. Timing is shown in Fig. 2 and the function implementation in Fig. 1.

The circuit can replace a digitally implemented variable clock and has the advantage of being continuously variable, rather than stepwise variable (step size equals...