84 results about "Chaotic oscillators" patented technology

A communication system having a transmitter chaotic signal generator and a receiver chaotic signal generator which when uncoupled generate state signals along substantially identical chaotic attractor trajectories in an out of phase relation. A controller controls the transmitter chaotic signal generator to transmit a state signal having segments of the deterministic state trajectory which identify a subsequent length of the deterministic state trajectory matching an input N-bit sequence. A receiver coupler receives the transmitted state signal and, if the signal is above a threshold for a duration of approximately two bit periods, synchronizes the receiver chaotic signal generator to the segment of its deterministic state trajectory indicated by the state signal to generate, with or without coupling, the subsequent length of that state trajectory matching the input N-bit sequence. A receiver symbol detector reconstructs the N-bit sequence based on the receiver chaotic oscillator state signal.

The invention discloses a multi-frequency weak signal detection method for detecting the failure of a rotor in the early stage. A related method is adopted to conduct prophase noise removal, and a chaotic oscillator array scanning method is adopted to realize simultaneous detection of a plurality of frequency weak signals represented by the same failure, that is, signals with noise are denoised through related calculation, a related function is sent to the chaotic oscillator array and serves as a part of chaotic system periodic driving force, and the weak periodic signal of a signal to be detected can be detected through the change of chaotic system phase locus. The method improves the signal-to-noise ratio of the signal to be detected, and completes the detection of multi-feature weak signal through identifying the state of Duffing oscillator, namely the change of phase locus pattern. Therefore, the method has the advantages of simplicity, intuition, definite physical significance and high detection signal-to-noise ratio. Furthermore, the method is capable of completing the weak signal detection of a plurality of known frequencies and easy for engineering realization, thereby having greater development potential.

The invention discloses a wien-bridge chaotic oscillator based on a firs-order generalized memory resistor. The wien-bridge chaotic oscillator based on a firs-order generalized memory resistor comprises a capacitor C1, a capacitor C2, a capacitor C3, a inductor L, a resistor R1, a resistor R2, a resistor R3, a resistor R4, an operational amplifier U1, and the memory resistor M comprised of a diode bridge cascade RC filter; wherein, the memory resistor M comprised of the diode bridge cascade RC filter comprises a diode D1, a diode D2, a diode D3, a diode D4, a resistor R0, and a capacitor C0. The wien-bridge chaotic oscillator based on a firs-order generalized memory resistor according to the invention is simple in structure, and through regulating reference values of elements of the circuit, the wien-bridge chaotic oscillator can exhibit different chaotic characteristics and obtain a chaotic behavior with complex dynamic characteristics. The memory resistor equivalent circuit according to the invention has no limitation of being grounded, i.e. the equivalent input end requires no ground processing and enables to be connected in series into the existing oscillating circuit. The dynamic characteristics of the memory resistor chaotic circuit according to the invention do not depend on the initial state, and the complex nonlinear physical phenomenon is avoided effectively.

The invention relates to a weak signal detection circuit based on a chaotic oscillator. A power supply module in the circuit provides +15V, -15V and +5V direct current voltages for the whole circuit. A control module mainly controls a signal generation module to generate a control signal and adjust the parameters of a chaotic detection circuit module. A display module displays the frequency and intensity of the control signal in the chaotic detection circuit module and the system detection frequency scanning range. An input module adjusts the system frequency scanning range. The signal generation module generates the control signal required. An amplitude adjusting module adjusts the control signal as a chaotic threshold value and then is merged with a signal to be detected and sent to the chaotic detection circuit module. According to the weak signal detection circuit based on the chaotic oscillator, output phase diagrams are observed by inputting the frequency scanning range, the frequency scanning interval and the frequency scanning step length to identify the weak signal.

Described herein is a combination of mixed-signal hardware and software that is capable or realizing hybrid chaotic oscillators that can be tuned digitally. This includes the type/class of chaotic oscillator, initial conditions, nonlinear elements, thresholds, nonlinear event surfaces, delays, etc. At the same time, tunable methods of how to use the chaotic oscillator information to encrypt and decrypt both analog and digital information is presented. This will make the secure information not vulnerable by digital information compromises or hardware breach.

The invention discloses a chaos-based method for detecting and classifying early single-point faults of a mechanical component. The method comprises the following steps of: processing conventional sample fault signals in different states of the mechanical component to establish check intervals for different fault types; acquiring fault characteristic frequencies corresponding to all single-point fault states of the mechanical component to construct a frequency matrix of a Duffing chaotic oscillator; solving critical thresholds of periodic driving force amplitudes corresponding to different fault characteristic frequencies to construct a frequency-threshold matrix; and finally, adding a signal to be detected to calculate the maximum Lyapunov exponent matrix M, checking according to data inthe M, calculating correlation dimension of the signal to be detected if a fault signal is available, and classifying the faults to determine a fault mode in comparison with the established correlation dimension intervals for different fault types. By adopting the method, the early single-point faults of the mechanical component are detected and classified; and the method has high noise resistance capacity and extremely high fault detection success rate.

The invention provides a space network cross-domain anonymous identity authentication method based on hyper-chaos encryption, relates to the technology of space information network, and solves the problem that the security mechanism applied in the conventional network cannot be directly applied to space network, and space cross-domain identity authentication cannot be realized. Provided is a space network cross-domain anonymous identity authentication method based on hyper-chaos encryption. The method includes two parts: a register stage and an authentication stage, a chaos algorithm is sensitive to initial conditions and control parameters, the structure is complex, prediction and analysis are difficult, and pseudo random sequences with good randomness and complexity are provided so that the chaos is applicable to encryption. A quantum cellular neural network is a cellular neural network structure coupling via quantum cellular neural network automata, complex linear dynamic features are obtained from the polarizability and quantum phase of each quantum cellular automaton, a nano-scale hyper-chaos oscillator can be constructed, the power consumption is low, the integration level is high, and the application requirement of space network satellite nodes can be better met.

The invention discloses a chaos-based early-stage single point of failure detection and classification method for mechanical part. The method comprises the following steps that: firstly, processing existing sample fault signals, under different states, of the mechanical part, and establishing verification intervals of different fault types; secondly, obtaining fault feature frequency correspondingto all single-point failure states of the mechanical part to construct the frequency matrix of a Duffing chaotic oscillator; thirdly, solving the critical threshold of a corresponding periodic stimulating force amplitude under different fault feature frequencies, and constructing a frequency-threshold matrix; and finally, adding a signal to be detected to calculate a maximum Lyapunov index matrixM, carrying out verification on data in the M, calculating the correlation dimension of the signal to be detected if a fault signal exists, carrying out fault classification by contrasting with the established correlation dimension interval of different fault types, carrying out fault classification, and determining a fault mode. By use of the method, the detection and the classification of the early-stage single-point failure of the mechanical part are realized, anti-noise ability if high, and in addition, a fault detection success rate is high.

Through study of loopholes of a TCP congestion control mechanism used by LDDoS (Low-rate Distributed Denial of Service) attacks and time frequency characteristics of network traffic, an LDDoS attack detection method based on chaotic Dufing oscillators obtains through induction that the essence of a problem of LDDoS attack detection is a problem of extraction of 'weak' square wave signals, the cycle of which is RTO<min>, under strong TCP background noises, the cycle of which is RTT. On the basis of using a Duffing system to detect the weak periodic signals, a basic idea and a concrete realization method for using a Duffing equation to construct chaotic oscillators and detect LDDoS attacks are invented so that a technology of using a double-Duffing-osicillator differential chaotic system to estimate attack parameters is realized. Through carrying out of a series of simulation tests in combination with experiment result analysis, feasibility of a detection model and an estimation method is verified and an objective of LDDoS attack detection is realized.

The present invention discloses an equivalent circuit model of chaotic oscillator based on a memcapacitor and a memory sensor. The model comprises an integrated operational amplifier chip U1, an integrated operational amplifier chip U2, a multiplying unit U3, a multiplying unit U4 and a multiplying unit U5; the integrated operational amplifier chip U1 mainly achieves reverse proportion operation and integral operation; the integrated operational amplifier chip U2 mainly achieves summation operation and integral operation; the multiplying unit U3, the multiplying unit U4 and the multiplying unit U5 achieve multiplying operation of two signals; and the U1 and the U2 employ LF347, and the U4 and the U5 employ AD633. The model comprises two integrated operational amplifier chips and three multiplying units so as to allow the structure to be clear and simple and easy to implement.

The invention discloses a true random number generation method and device with a detection and correction function. A random number is taken as an important component of a cryptosystem and is widely applied to a security system. The random number comprises a session key, an initial vector and a digital signature. The device is composed of an entropy source module, a sampling module, an XOR logic gate, a cellular finite state machine, a test module, a CPU and a selection controller. The entropy source module is composed of two identical oscillator structures. Each oscillator is a chaotic oscillator structure based on an autonomous Boolean network. The entropy source module can generate wide spectrum and high bandwidth chaotic signals. After a random sequence is tested through the test module, whether the sequence passes the test or not is judged through the CPU. The sequence is directly output if the sequence passes the test. Data is returned and enters a postprocessing module through an XOR circuit if the sequence does not pass the test. Moreover, a selection controller selects different postprocessing modes to process the data. The processed data enters the test module for test again, until the data passes the test. A random code sequence generated by the invention can pass a random number industry standard test.

The invention provides a novel power system harmonic and inter-harmonic wave detection and estimation method based on a chaotic oscillator, aiming to solve the problems that a power system harmonic and inter-harmonic wave detection and estimation method is bad in resolution of harmonic and inter-harmonic waves with similar frequency and is weak in noise interference resistance capability. The method includes two parts: a variable metric type double coupling intermittent chaotic oscillator through the integration of a variable metric algorithm and a double coupling intermittent chaotic oscillator array method, which is characterized by high resolution in signal frequency to be detected and high noise interference resistance capability and is capable of performing synchronous effective detection and high-precision frequency estimation on the harmonic and inter-harmonic waves at a low signal to noise ratio; and a new method for sinusoidal signal amplitude and phase synchronization estimation based on the phase climacteric double coupling chaotic oscillator, which is capable of realizing high-precision amplitude and phase estimation of harmonic and inter-harmonic waves under the condition of strong interference noises.

The invention discloses a detecting method based on a multi-frequency stimulation Duffing chaotic oscillator weak signal detection system. The method comprises the following steps that 1) the multi-frequency stimulation Duffing chaotic oscillator weak signal detection system is established, namely a free-oscillation Duffing chaotic oscillator mathematic model is selected; detected signals which do not contain noise are decomposed in a different-frequency-harmonic-wave-superposition mode; the detected signals which do not contain noise are used as Duffing chaotic oscillator stimulation item factors, the multi-frequency stimulation Duffing chaotic oscillator weak signal detection system is established; an equation set form is rewritten, an equation set is solved, F0 corresponding to a phase transformation critical state which is sensitive to driving force and is good in identifiability is used as initial driving force of the detection system; 2) the detected signals are introduced into the multi-frequency stimulation Duffing chaotic oscillator weak signal detection system, and detection is carried out according to the phase transformation law. According to the method, when multi-frequency signals are detected, the uncertain influence of the detected signals on the phase transformation law of a single-frequency stimulation chaotic oscillator detection system can be removed or lowered.

The invention relates to a disturbed chaotic double-helix random number generator comprising a linear feedback shift register. The disturbed chaotic double-helix random number generator is characterized by further comprising a control signal generation circuit, a capacitor array, a double-helix oscillator and a sampling quantization circuit. The linear feedback shift register is connected with the control signal generation circuit, and used for outputting a pseudorandom sequence; the control signal generation circuit is connected with the capacitor array, and used for receiving the pseudorandom sequence, generating and outputting a control signal; the capacitor array is connected with the double-helix oscillator, and used for receiving the control signal and outputting an array capacitance value; the double-helix oscillator is connected with the sampling quantization circuit, and used for receiving the array capacitance value and then outputting a chaotic signal; and the sampling quantization circuit receives the chaotic signal, converts the chaotic signal into a digital signal and outputs the digital signal.. Since the initial value of the chaos-based double-helix oscillator is sensitive and unpredictable, the chaotic double-helix oscillator can continuously oscillate and generate output without outside intervention. For the outside disturbance, the representation of the chaotic oscillator is variation of track, and the variation of track is also hard to predict for the complexity.

The invention discloses a method for improving the anti-noise capability of a Duffing chaotic oscillator for detecting weak resonance signals. The method comprises the following steps of establishinga Holmes-Duffing equation for modifying a nonlinear restoring force item coefficient and an order and converting the state equation into a Holmes-Duffing system state equation with any frequency to solve a maximum Lyapunov indexl l determining a critical threshold value of a Duffing system amplitude reverse subtraction algorithm according to the sign symbol change of the maximum Lyapunov index; and carrying out weak resonance signal detection under different noise variances on an actual amplitude-frequency characteristic curve obtained by open-loop frequency sweeping by utilizing the improvedHolmes-Duffing equation and an amplitude inverse subtraction algorithm. The method has stronger noise interference resistance in the aspect of detecting weak resonance signals, is high in detection precision and small in relative error, has great significance in practical application, and thus has good application prospects.