Documation, Inc.

Robert C Snyder

Willard T Bushman

A card reader for reading data cards of the type having columns of machine-readable information thereon and transmitting data outputs representative of this information to an interface, includes a read station for sensing the information in each column and generating corresponding data outputs. A latching circuit receives data outputs from the sensing means and transmits the data outputs to the interface responsive to a strobing signal. A timing wheel is employed to detect the velocity of the cards during transport through the read station to provide an output proportional to velocity. A train of pulses is generated for each column responsive to the velocity output, and the period of the pulse train is adjusted to compensate for increases or decreases in the velocity of the card through the read station, by employing a phase-locked loop circuit. The pulse train is then decoded to generate the strobing signal to the latching means coincident with a first predetermined pulse in the train, and for utilizing other pulses in the train to generate signals initiating other functions of the reader.

Data card reader employing synchronization and resynchronization means

This invention relates to a method and apparatus for reading periodic timing marks from a moving printing band and for generating synchronous timing marks during the passage of a missing timing mark on the printing band. Two timing mark sensors are positioned adjacent the printing band or belts but spaced from each other by a distance several multiples of the spacing between timing marks. The downstream or primary sensor is used to detect the passage of timing marks adjacent thereto. When the missing pulse passes the upstream or secondary detector, an electronic switch transfers the output line to the upstream sensor until the missing pulse passes the primary sensor. As the missing timing pulse passes the primary sensor, the switch is actuated to couple the output line again to the primary sensor. In this manner a continous stream of synchronized timing pulses will be generated by the sensors even during the period when the missing timing pulse passes adjacent the primary sensor.

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Melbourne, FL, United States of America

Robert C Snyder