Fairchild Camera and Instrument Corp.

General Instrument Corporation

Service Distributors, Inc.

Eric G Breeze

Peter H Alfke

R Fred Pfost

Charles H Alford

This system is for use with multicharacter displays. Each character being composed of a plurality of segments which are of a unidirectional type, e.g. an LED. Selected segments of each character are sequentially illuminated to display alphanumeric or other symbols. In this system the number of interconnections between the display and a drive circuit is greatly reduced. For example an 8-character display where each character has 7 segments would require only 8 leads.

Bi-directional drive multiplexed display system

A control system is described for activating a machine using magnetic signals encoded on a magnetic card, tape or equivalent member. The magnetic signals are pulse-width-modulated and, in one embodiment, also sawtooth-modulated. A means is provided which is responsive to the magnetic signals for generating a first and a second number. The first number corresponds to the number of times the magnetic card is usable for activating a machine. The second number is provided for identification and validation purposes. Means are also provided for reducing the number of times the card can be used each time it is used to activate a machine and for visually displaying that number on a visual display device. The use of skewed recording and reproduction heads is also described for improving signal discrimination and security against the usability of fraudulently produced magnetic cards.

Binary system for magnetic card actuation for laundry machines

A phase-locked loop frequency synthesizer is described not having the uncontrolled modulation of its output normally associated with such a synthesizer due to a detection dead band inherent in the phase/frequency comparator which is a principal part thereof. The frequency synthesizer includes, as is conventional, a reference oscillator and an oscillator for generating the synthesizer output. The comparator is also included as is conventional to detect unwanted deviations of the phase and frequency of the synthesizer output so they can be corrected. In order to compensate for the inability of the comparator to detect small unwanted deviations, a pulse generator is added to the synthesizer to apply what is, in effect, an intentional periodic phase error signal greater than the dead band difference. This causes the phase of the desired output to be corrected in a controlled manner which will prevent undesired frequency modulation of its output.

Phase-locked loop frequency synthesizer

A fine tunable electronic channel select system for controlling the varactor tuner of a television receiver or the like and including a dual mode prescaler for dividing the local oscillator (VCO) frequency of the tuner by a first divisor and then by a second divisor to produce a selectively variable average divide during a sample period, a programmable digital divider for dividing the output of the prescaler by a predetermined divisor corresponding to a selected television channel, a channel selection mechanism for controlling the programmable divider, a signal source for generating a stable reference frequency, a frequency/phase comparator for comparing the output of the programmable divider with the reference signal to develop an error signal, an integrator/amplifier for integrating the error signal to develop a biasing signal for controlling the tuner, and a fine-tune control circuit for selectively controlling the length of time the prescaler operates in each of its two modes, thereby enabling incremental variation of the biasing signal to provide fine tuning of the varactor tuner.

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Los Altos, CA, United States of America

Eric G Breeze