62 results about "Non linear circuits" patented technology

This invention is about a novel estimation technique for generating a predistortion function to compensate for the AM-AM and AM-PM non-linear conversion distortions of non-linear power amplifiers or non-linear circuits. Based on the cumulative type of power amplifier output envelope, a non-parametric baseband predistortion function is derived. The non-parametric approach avoids any model mismatch. In addition, the technique does not need to demodulate the input signal. Furthermore, it minimizes the effect of the power amplifier non-linearity and significantly improves the system performance

An energy management system that facilitates the transfer of high frequency energy induced on an implanted lead or a leadwire includes an energy dissipating surface associated with the implanted lead or the leadwire, a diversion or diverter circuit associated with the energy dissipating surface, and at least one non-linear circuit element switch for diverting energy in the implanted lead or the leadwire through the diversion circuit to the energy dissipating surface. In alternate configurations, the switch may be disposed between the implanted lead or the leadwire and the diversion circuit, or disposed so that it electrically opens the implanted lead or the leadwire when diverting energy through the diversion circuit to the energy dissipating surface. The non-linear circuit element switch is typically a PIN diode. The diversion circuit may be either a high pass filter or a low pass filter.

A system and method are disclosed for waveform based variational static timing analysis. A circuit is divided into its linear circuit parts and non-linear circuit parts and modeled together, by a combination of linear modeling techniques, into linear equations that may be represented by matrices. The linear equations in matrix form may be readily solved by a computer such that an input waveform to an input pin of the circuit can be sequentially “pushed” through the various interconnects and logic networks of the circuit to an output pin. Output voltage waveforms are obtained at each stage of the waveform pushing and may be used to perform static timing analysis.

A class of modular, double-sided, edge-mounted printed circuit (PC) board modules and an associated modular network architecture for constructing stripline signal processing networks including high-power analog amplifiers and beam forming networks for driving multi-beam antenna systems. The stripline signal processing networks are characterized by network elements constructed from defined-length segments of transmission media configured to exhibit precisely determined phase and impedance characteristics. These circuits may also include conventional passive “lumped” electrical elements, such as resistors, capacitors and inductors; non-linear circuit elements such as diodes; and active electrical elements, such as amplifiers and transistors.

The invention relates to a method for detecting positive sequence, negative sequence, idle and harmonic currents of a power supply system. The detection method is based on three-phase voltage space vector oriented positive sequence synchronous coordinate rotation transformation, negative sequence synchronous coordinate rotation transformation and low-pass filtering. The method is very effective for detecting various positive sequence, negative sequence, idle and harmonic currents of three-phase four-wire and three-phase three-wire non-linear circuits. The method only transforms the tested current, and does not need to transform voltage. Therefore, the invention has the advantages of simple structure and clear conception. The invention is the simplest engineering method for dynamic and static idle and harmonic compensation.

A system for analyzing a model of an electronic circuit, which includes at least one non-linear circuit element, includes a computer. The computer replaces the non-linear circuit element with a linearized circuit model that approximates a behavior of the non-linear circuit element. The computer also inserts into an element matrix a calculated value that corresponds to the linearized circuit model for a prescribed or desired time step. The computer further performs a numerical operation on the element matrix to effectively invert the element matrix.

Signal amplifiers having a non-linear transfer function. A high speed (high bandwidth) circuit with a non-linear transfer function over a limited range of input signal is provided. By appropriate choice of components, the non-linear transfer function can be used to accurately approximate any monotonic function such as a square root transfer function. In another aspect, a piecewise non-linear circuit arrangement using a set of non-linear sub-circuits is provided to accurately generate a desired non-linear transfer function over an extended dynamic range of input signal. In one implementation of such a circuit, each of the sub-circuits approximates the desired non-linear function over a portion of the input range.

The invention relates to apparatus for detecting the presence or the absence of a signal carrier wave received by a receiver. The carrier wave is modulated by a digital signal at a symbol clock frequency. According to the invention, the apparatus includes: a non-linear circuit receiving the received signal or the received signal after it has been frequency transposed, the non-linear circuit supplying in particular a signal whose frequency corresponds to the symbol clock frequency; a narrow-band filter centered on the symbol clock frequency and supplying a filtered signal; detection means for detecting the filtered signal and for supplying a detection signal; and comparator means for comparing the detection signal with a reference value, the output signal from the comparator means constituting a signal indicating the presence or the absence of the carrier wave. The invention is particularly applicable to a receiver including automatic gain control apparatus placed upstream, and the indicator signal may optionally be applied to automatic frequency control apparatus.

A method is provided for providing an automated assistance to design an analog non linear circuit under transient conditions, and to a corresponding system. The method enables the circuit designer to consider with simulation the time reactive effects of generally nonlinear components, while keeping the significant and intuitive qualities of an analysis view design tool like the CAIRO+/CHAMS environment. The method includes at least a transient instant solving procedure producing a numerical simulation that uses a given set of sizes and biases to provide a set of local behavior parameters in at least one node at current time. This transient instant solving procedure includes an incremental iteration under transient conditions of an evaluation in an analysis view of a dependency graph of the functional structure of the circuit. An optional transient analysis performs a numerical simulation to provide a time dependent behavior simulation of the circuit, and a performance evaluation.

The driving device has a piezoelectric element 32, a supporting member 16 fixed to one end of the piezoelectric element 32, a driving shaft 18 fixed to the other end of the piezoelectric element 32, a movable member 20 that is movably held on the driving member 18, and a driving circuit 33 that applies the drive voltage to the piezoelectric element 32. The driving circuit 33 includes a self-oscillating circuit 34, 38 that oscillates at a series resonance frequency of the piezoelectric element 32 and a non-linear circuit 36, 40, 42, 44, 46 for adding distortion to the drive voltage that is applied to the piezoelectric element 32.

The invention relates to the technical field of secure communication, in particular to a hyper-chaotic signal generating method and a generating system thereof, wherein the hyper-chaotic signal generating method comprises the following steps: a sinusoidal signal is input to a non-linear circuit which can generate the hyper-chaotic signal, thereby changing the state equation parameter of the non-linear circuit which can generate the hyper-chaotic signal and causing at least two lyapunov indexes of a chaotic system to be larger than 0; the hyper-chaotic signal generating system comprises the non-linear circuit which can generate the hyper-chaotic signal and also comprises a sinusoidal signal generating device connected with a signal input end of the non-linear circuit which can generate the hyper-chaotic signal, and sinusoidal signal generating device outputs the sinusoidal signal to the non-linear circuit which can generate the hyper-chaotic signal, thereby changing the state equation parameter of the non-linear circuit which can generate the hyper-chaotic signal and causing the at least two lyapunov indexes of the chaotic system to be larger than 0.

A spectral enhancement system is disclosed that includes an input node for receiving an input signal, at least one broad band pass filter coupled to the input node and having a first band pass range, at least one non-linear circuit coupled to the filter for non-linearly mapping a broad band pass filtered signal by a first non-linear factor n, at least one narrow band pass filter coupled to the non-linear circuit and having a second band pass range that is narrower than the first band pass range, and an output node coupled to the narrow band pass filter for providing an output signal that is spectrally enhanced.

The model order reducing technology is one very useful technology for raising circuit simulating and verifying speed in improving circuit design scheme. The present invention establishes one kind of directly projecting method of reducing order of non-linear circuit model, and features the combination of direct projection and variation analysis in control theory. The sub-system obtained through variation analysis is used in constituting son projection matrix V1, V2, ..., Vn; and the relation between the original system and the son system is then used in constituting united projection matrix V. The projection matrix V is finally used in realizing direct projection of one approximate non-linear system on the original non-linear system. Compared with the order reducing the sub-system method, the present invention has greatly raised order reducing precision and efficiency.

A Class C bipolar transistor amplifier including circuit means having a non-linear, high-current, low-knee voltage transfer characteristic in series with the emitter RF choke of a common base bipolar transistor, which increases the emitter bias voltage, and in turn forces the amplifier deeper into Class C operation during overdrive, effectively limiting the output power. In one embodiment, a low ohmic resistor and a MOSFET device are connected in series with the emitter RF choke of a common base bipolar transistor Class C amplifier. An active feedback control loop implemented with conventional operational amplifier (OP AMP) circuitry controls the MOSFET device so as to operate in the knee region of its current-voltage characteristic during power overdrive. In a second embodiment, a single non-linear circuit element such as a constant current diode having a high-current, low-knee voltage transfer characteristic is connected in series with the emitter RF choke. The constant current diode consists of a depletion mode MOSFET or JFET having the gate directly connected to the drain.

The invention provides a differential chaotic system signal generating device which can generate any differential chaotic system, change system parameters and system calculation initial values and generate a chaotic signal without using a non-linear circuit. The differential chaotic system signal generating device comprises a system input module, an initial value input module, an equation calculation module and a signal output module, wherein the system input module is used for inputting a differential chaotic equation; the initial value input module is used for inputting the calculation initial values of the differential chaotic equation; the equation calculation module receives the differential chaotic equation and the calculation initial values inputted by the system input module and the initial value input module, and solves the differential chaotic equation; and the signal output module is used for converting the solution sequence obtained by the solution module to obtain a simulated chaotic signal, and carries out D/A conversion of the simulated chaotic signal to output an analog chaotic electric signal. The invention also provides differential chaotic system signal generating method. Any differential chaotic equation can be inputted, multiple differential chaotic signals can generated, calculation initial values and system parameters can be changed, and reflecting the dynamical characteristics of chaotic signals are reflected.

The invention discloses a high-precision multi-range weak current detection system comprising a reset circuit and a single-chip microcomputer control circuit connected with the reset circuit by a line. The single-chip microcomputer control circuit is connected with a dynamic zero-adjusting circuit, a process amplifying circuit, a signal selecting circuit, a pre-amplifier circuit, a reference signal generating circuit, and a sine wave signal generating circuit by the line. According to the invention, time-sharing gating is realized by using an analog switch switching circuit, so that the detected current passes through the linear amplification circuit or non-linear circuit and then passes through the process amplifying circuit, a phase-sensitive demodulation circuit, and a low-pass filtering circuit. Range-dividing measurement is carried out; the product cost is reduced; the dynamic range of measurement is improved; and the signal to noise ratio is improved, thereby enhancing the measurement precision.

A pre-characterised high frequency signal (14) is provided by means of a non-linear circuit, for example an amplifier circuit (10), fed with a first signal (12) with a component at a first, fundamental, frequency (FO). The amplifier circuit generates an output signal comprising harmonic components (14_h1, 14_h2, 14_h3) having stable and predetermined phase relation relative to each other. Information concerning the phase relation of the harmonic frequency components is provided, for example by means of a data file (16). At least two of the harmonic components are at the tenth or lower harmonic frequencies. The signal strength of such low-order harmonic components may be relative high, thus enabling the provision of a pre-characterised high frequency multi-tone signal from the amplifier circuit with high signal to noise ratio.

The invention relates to a method for determining passive-intermodulation quantity of a net-shaped reflecting surface antenna, and belongs to the technical field of space special effects of satellite-borne microwave components. The method makes time-domain calculation of an electrically-large-size net-shaped reflecting surface antenna possible through simplified calculation of an established equivalent mesh model of an actual net-shaped reflecting surface antenna, ensures calculation accuracy, combines a passive-intermodulation analysis method of a non-linear circuit model, obtains generated passive-intermodulation output quantity of each order through one-time simulation when different frequencies are input, eliminates the annihilation effect on signals with small passive-intermodulation quantity due to the input of large signals through an ideal circuit model, eliminates the annihilation effect on signals with small passive-intermodulation quantity caused by accumulated error in time-domain analysis, successfully solves the difficulties of accurate electromagnetic field distribution calculation and passive-intermodulation analysis of the electrically-large-size net-shaped reflecting surface antenna, fills the blank of net-shaped reflecting surface antenna passive-intermodulation analysis technology, and has broad technology market and application prospect.

A system and method is provided for coupling a power source across a rotation boundary. A generator converts a DC source on the stationary side of a rotation boundary to a square-wave at a determined frequency. The generator output connects through a transmission line and a first transformer to a set of stator rings. A set of rotor rings form a set of coupling capacitors with the stator rings. The rotor rings connect through a second transformer and a transmission line to a non-linear circuit capable of converting the square-wave to a DC voltage and current that can power a load on the rotating side of the rotating boundary in which the power is nearly equal to the power available from the source on the stationary side of the rotation boundary.

An analysing method of wavelet includes building up nonlinear system equation, mapping actual analog zone onto wavelet analog zone, carrying out series expansion for system variable and carrying out system discretization, obtaining wavelet coefficient by solving the equation and calculating out signal value of system variable on discrete time point, utilizing Fourier series expansion formula in frequency domain to obtain continuous requency spectrum.

The present invention discloses an AC-DC hybrid system stability analysis method and system based on a mixed potential function. The method comprises the following steps of: establishing an equivalentmodel of a mixed potential function theory; constructing a mixed potential function of an AC-DC hybrid system to be researched by employing the equivalent model; and reconstructing the mixed potential function, solving a characteristic root according to the reconstructed mixed potential function, and employing a mixed potential function third stability theory to obtain stability criteria of the AC-DC hybrid system. The method can establish the potential function of the system in terms of energy to avoid complex value integration, facilitate obtaining of dynamic safety criteria in an analysismode and provide basis for formulation of a system safety operation control strategy, and the construction of the potential function of the mixed potential function method aims at a current and a voltage of a special branch of a general non-linear circuit network without relating to the electric quantity of a rotation unit, so that the AC-DC hybrid system stability analysis method and system basedon the mixed potential function are very suitable for construction of the energy function of the AC-DC hybrid system by taking power electronic equipment as a principal thing.