Chaotic signal enabled low probability intercept communication
First Claim
1. An autonomous chaotic circuit having a first pair of circuit output terminals and a second pair of circuit output terminals and being fully differential, the autonomous chaotic circuit comprising:
- a first circuit having a pair of first input terminals and a pair of first output terminals, the pair of first input terminals coupled to the first pair of circuit output terminals in a positive feedback configuration;
a multiplier circuit coupled to the first circuit in a positive feedback configuration, the multiplier circuit having a pair of multiplier input terminals and a pair of multiplier output terminals, the pair of multiplier input terminals being coupled to the pair of first input terminals, and the pair of multiplier output terminals being coupled to the pair of first output terminals forming a first pair of common output terminals including a first common output terminal and a second common output terminal;
a first LC circuit having a first inductor coupled to a first capacitor in parallel, the first LC circuit being coupled to a reference voltage at one terminal;
a second LC circuit having a second inductor coupled to a second capacitor in parallel, the second LC circuit being coupled to the reference voltage at one terminal;
a first resistor coupled between the first LC circuit and the first common output terminal, a node between the first resistor and the first LC circuit being a third common output terminal; and
a second resistor coupled between the second LC circuit and the second common output terminal, a node between the second resistor and the second LC circuit being a fourth common output terminal, the third common output terminal and the fourth common output terminal forming a second pair of common output terminals;
wherein the first circuit and the multiplier circuit are implemented using HBT, andwherein the first inductor, the second inductor, the first capacitor, and the second capacitor are implemented by passive inductors and passive capacitors.
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Accused Products
Abstract
A circuit for generating chaotic signals implemented using heterojunction bipolar transistors (HBTs) and utilized in low probability intercept communications. The HBT chaotic circuit generates truly random analog signals in the GHz range that are non-repeating and deterministic and may not be replicated by preloading a predetermined sequence. A fully differential autonomous chaotic circuit outputs two pairs of chaotic signals to be used in a communication system. As it is impossible to generate identical chaotic signals at the transmitter and receiver sites, the receiver itself sends the chaotic signal to be used for encoding to the transmitter. The receiver includes a chaotic signal generator and digitizes, upconverts, and transmits the generated chaotic signal to the transmitter. The transmitter uses the received chaotic signal to code data to be transmitted. The receiver decodes the transmitted data that is encoded by the chaotic signal to retrieve the transmitted data.
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Citations
7 Claims
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1. An autonomous chaotic circuit having a first pair of circuit output terminals and a second pair of circuit output terminals and being fully differential, the autonomous chaotic circuit comprising:
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a first circuit having a pair of first input terminals and a pair of first output terminals, the pair of first input terminals coupled to the first pair of circuit output terminals in a positive feedback configuration; a multiplier circuit coupled to the first circuit in a positive feedback configuration, the multiplier circuit having a pair of multiplier input terminals and a pair of multiplier output terminals, the pair of multiplier input terminals being coupled to the pair of first input terminals, and the pair of multiplier output terminals being coupled to the pair of first output terminals forming a first pair of common output terminals including a first common output terminal and a second common output terminal; a first LC circuit having a first inductor coupled to a first capacitor in parallel, the first LC circuit being coupled to a reference voltage at one terminal; a second LC circuit having a second inductor coupled to a second capacitor in parallel, the second LC circuit being coupled to the reference voltage at one terminal; a first resistor coupled between the first LC circuit and the first common output terminal, a node between the first resistor and the first LC circuit being a third common output terminal; and a second resistor coupled between the second LC circuit and the second common output terminal, a node between the second resistor and the second LC circuit being a fourth common output terminal, the third common output terminal and the fourth common output terminal forming a second pair of common output terminals; wherein the first circuit and the multiplier circuit are implemented using HBT, and wherein the first inductor, the second inductor, the first capacitor, and the second capacitor are implemented by passive inductors and passive capacitors. - View Dependent Claims (2, 3, 4, 5)
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6. A method for autonomous and differential generation of a pair of chaotic signals, the method comprising:
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generating a differential pair of currents by supplying a differential control voltage and positive feed back to a negative resistance circuit, the negative resistance circuit implementing a negative resistance and having nonlinear input-output characteristics; generating resonance by providing the differential pair of currents to a pair of parallel LC circuits through a pair of resistors; obtaining a first chaotic signal from a differential pair of voltages output by the negative resistance circuit at nodes before the pair of resistors; and obtaining a second chaotic signal from the differential pair of voltages output by the negative resistance circuit at nodes after the pair of resistors, wherein the negative resistance circuit includes a parasitic capacitance, and wherein the resonance generated is substantially in the GHz range. - View Dependent Claims (7)
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Specification