Data card reader employing synchronization and resynchronization means
US4114031A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1975 |
| Grant date | Sep 12, 1978 |
| Priority date | — |
| Expiry date | Aug 29, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/016
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.