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Title: Security system for a solid state device
Abstract:
The security system is adapted to be utilized in conjunction with a device such as an electronic calculator having solid state circuit elements formed on chips wherein the elements perform predetermined functions. The system comprises a gate formed on one of the chips for interconnecting at least two of the circuit elements in response to an enable signal. A data generator is provided and an encoding device encodes the data from the data generator as a sequence of binary signals. A reference encoder generates a preselected sequence of binary signals. A comparing device is connected to the encoding device and the reference encoder and is operable to generate and apply the enable signal to the gate when the sequence of signals from the encoding device matches the preselected sequence of signals from the reference encoder.
Other info: Inventors: Schulman, Lawrence S. (Hiafa, IL, US) Application Number: 648920 Filing Date: 1976-01-14 Publication_date: 1979-02-13 Assignee: Primary Class(es): 725/20 348/725, 361/172, 708/135, 713/183 Other Classes: US Patent Ref:
Other Refs: Other References: Gernsback, "An Open Letter to the Radio Industry," Radio-Craft, p. 155, Sep. 1938. Ellis, Science and Mechanics, vol. 36, No. 3, Mar. 1965. | |