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.

Abstract: A bar code reader and decoder for reading and decoding linear bar coded information through the use of a logarithmic time base generator. The ratio of the widths of the coding segments are computed for decoding the bar coded data by utilizing a logarithmic time base generator for providing a logarithmic measure of the widths of preselected coding segments and accumulating the logarithmic timing signals in up/down counters to provide a logarithmic representation of the ratios of the widths of the segments. The resultant count of an up/down counter is applied to a translation table to provide a signal representative of equality in widths between compared coding segments or the relative widths in terms of greater than or less than in the direction of scanning.

Abstract: An improved wideband frequency multiplier characterized as follows: a saw-tooth signal generator supplying a saw-tooth wave having a frequency equal to the frequency to be multiplied, the level of the voltage wave varying between a reference level and a maximum which is related to the frequency to be multiplied; storage means for storing a voltage equal to, or closely approaching the maximum voltage value of the saw-tooth wave; a voltage divider having several outputs, each of which provides an output which is a given fraction of the stored voltage; a number of comparators each of which corresponds to and is coupled to an output of the voltage divider, each comparator comparing the instantaneous value of the saw-tooth voltage with the voltage supplied by the corresponding output of the voltage divider, and supplying a first level signal when said instantaneous value is lower than the voltage supplied by said corresponding output, and a second level signal when it is higher; and logical circuits combining the

Abstract: A magnetic ink character reading system is provided in which multi-element read heads are positioned in a spaced apart and staggered arrangement. Data signals occurring in the analog responses of the read heads are detected, and converted to discrete logic level signals under the control of a dynamically adjustable threshold. The logic level signals of each read head are sampled in response to independent data sample signals which are phase locked to the data rate of the respective read head. NRZ (non-return-to-zero) data signals formed thereby are synchronized to a common fixed frequency, and serialized faithfully to represent the characters appearing on documents passing the read heads.