Rolling code security system
DCFirst Claim
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1. A transmitter comprising:
- an oscillator for generating a radio frequency oscillatory signal;
a source of a sequence of binary codes, successive binary codes in the sequence being different from predetermined preceding binary codes in the sequence;
trinary code generator for converting said sequence of binary codes to a sequence of trinary codes; and
a transmitting apparatus for modulating the radio frequency oscillatory signal with the binary codes to produce a modulated trinary coded radio frequency signal.
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Abstract
A rolling code transmitter is useful in a security system for providing secure encrypted RF transmission comprising an interleaved trinary bit fixed code and rolling code. A receiver demodulates the encrypted RF transmission and recovers the fixed code and rolling code. Upon comparison of the fixed and rolling codes with stored codes and determining that the signal has emanated from an authorized transmitter, a signal is generated to actuate an electric motor to open or close a movable barrier.
89 Citations
26 Claims
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1. A transmitter comprising:
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an oscillator for generating a radio frequency oscillatory signal;
a source of a sequence of binary codes, successive binary codes in the sequence being different from predetermined preceding binary codes in the sequence;
trinary code generator for converting said sequence of binary codes to a sequence of trinary codes; and
a transmitting apparatus for modulating the radio frequency oscillatory signal with the binary codes to produce a modulated trinary coded radio frequency signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 25, 26)
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17. A transmitter for authorizing access to a secure area by a control actuator receiver, comprising:
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an oscillator for generating a radio frequency oscillatory signal;
a binary code generator for generating a sequence of binary codes, predetermined ones of the binary codes being different from others of the binary codes of the sequence;
a trinary code generator responsive to the binary codes for generating three-valued or trinary codes; and
a transmitting apparatus for modulating the radio frequency oscillatory signal with the trinary codes to transmit a modulated trinary coded radio frequency signal to the control actuator receiver. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification