31results about How to "Eliminate Nonlinear Distortion" patented technology

A highly linear analog-to-digital (ADC) conversion system has an analog front-end device in cascade with a standard ADC converter, and a tunable digital non-linear equalizer. The equalizer corrects the quantization distortion, deviations from ideal response, and additive noises generated by the analog front-end device and ADC converter. The equalizer is formed by three main parts: Generate Function Streams Unit, Finite Impulse Response FIR filters and a summer. The equalizer receives the unequalized output from the ADC converter and generates a plurality of monomial streams in a systolic fashion. Each of the monomial streams is passed through a corresponding linear finite impulse response FIR filter. A convolution sum of all outputs from the FIR filters produces a unique equalized output with the non-linear distortion reduced to a satisfactory level. The FIR filter coefficients are determined by an Identity Equalizer Coefficient Unit, and a Test Signal Generator with different types of test signals. The FIR filter coefficients are set to minimize an error function.

This invention discloses a microphone echo elimination device and method, which eliminates echo between microphone and sound circuit, wherein, the device comprises long frame adjust module to combine one self adaptive filter parameter data frame for self adapting filter.

The invention provides an optical coherence tomography (OCT) system correction method. The method comprises the steps of obtaining correction data and correcting, wherein in the step of obtaining correction data, the OCT system scans a reference slide to obtain the relation function between the reference slide measured value and different depth positions; and in the correcting step, the obtained detection data are corrected according to the relation function between the thickness and the depth positions.

The present invention is related to a pipelined analog-to-digital converter, ADC, for converting an analog input signal into a digital signal comprising—a plurality of comparing means having tuneable thresholds for comparing an input signal with; at least two of said given thresholds being different and—a plurality of amplifying circuits,—wherein said plurality of comparing means is configured to form a hierarchical tree structure, said hierarchical tree structure having a plurality of hierarchical levels, wherein at least one of said hierarchical levels is associated with at least one amplifying circuit of said plurality of amplifying circuits, said at least one amplifying circuit generating the input of at least one comparing means at the next hierarchical level and—wherein said plurality of hierarchical levels comprises means for setting said tuneable thresholds in accordance to the output of previous hierarchical level so that non-linear distortion of the preceding hierarchical level is removed.

The present invention relates to a bilinear interpolation method-based laser galvanometer graphic correction algorithm and the core of the algorithm is composed of a bilinear interpolation method. Mathematically, the bilinear interpolation method is the extension of the linear interpolation for an interpolation function containing two variables. The core idea of the laser galvanometer graphic correction algorithm is composed of the primary linear interpolation conducted respectively in two directions. Experiments show that, the correction algorithm can eliminate the linear distortion and the nonlinear distortion occurred during the graphic scanning process of a laser galvanometer. Meanwhile, the algorithm can correct the comprehensive error generated during the scanning process of the laser galvanometer. Therefore, the algorithm provides a satisfactory correction effect for the correction of laser marking graphics.

The embodiment of the invention discloses a method for correcting the nonlinear distortion of a communication signal, relating to the field of wireless communication and being used for solving the signal distortion and the deformation of modulated constellation points caused by the nonlinear characteristic of a radio frequency power amplifying device. Through the adoption and the simplification of a self-adaptive fuzzy neural network, namely a tool which can be used for nonlinear function approximation, the method for eliminating the nonlinear distortion can enable the nonlinear characteristic of the radio frequency amplifying device to fully approximate and be compensated.

The present invention discloses a multi-purpose linear circuit module, and belongs to the basic electronic circuit of the electrical field. The module adopts the characteristic of the linear relationship between the control voltage and the output current in the complementary push-pull circuit of the field-effect tube and the characteristic of no grid current in the field-effect device, matches the peripheral auxiliary circuit, and thus realizing the linear transmission of voltage signals, the linear conversion from voltage signals to current signals, and the linear transmission of current signals. In particular, the transmission of the current signals has no relevance to the parameters of devices in the circuit, and is the real zero-distortion transmission. The circuit module is mainly used in the internal amplification circuit of the audio equipment, and can also be used in other devices which require precise transmission of electric signals. The amplifier of electric signals, which comprises the circuit module, completely has no necessary negative feedback of the loop, thus eliminating the instant intermodulation distortion of the amplifier and improving the instant hearing effects; and the circuit module provides an optimum proposal for the simulating amplification circuit.

A method for signal processing is provided. The method includes: obtaining a predistortion signal for compensating nonlinear distortion generated by a transmission path; adding the predistortion signal to the transmission path to compensate the nonlinear distortion; and outputting the nonlinear distortion compensated signal by the transmission path. With the above method, the nonlinear distortion of the transmission path can be compensated without modifying a current transmission path, thereby enhancing transmission performance of a transmitter by using a simple structure.

The invention discloses an optical transmission method and device based on power spectrum shaping. Direct detection, namely square demodulation, of high-spectrum-efficiency optical signals is supported. According to the invention, a power spectrum shaping modulation method is adopted at a sending end, and the modulation method realizes multi-level improved dual-binary coding and multi-level offsetdual-binary coding by biasing a Mach-Zehnder optical modulator at a zero point, namely Vpi, and increasing level in combination with nonlinear precoding, and can also realize residual sideband improved dual-binary coding in combination with an optical filter; inter-symbol interference of received signals is removed at a receiving end by adopting nonlinear equalization, and meanwhile, the difference of received levels can be fed back to a transmitter, so that non-equidistant multi-level modulation is realized, and the nonlinear equalization complexity is reduced. According to the method, signals needing coherent demodulation can be directly detected through proper nonlinear precoding and nonlinear equalization, so that the hardware complexity is reduced.

A method of receiving a target signal existing in a wideband signal. The method includes the steps of receiving the wideband signal, removing the target signal from the wideband signal to obtain an interference signal, transforming the interference signal into an inverse interference signal, and finally combining the wideband signal with the inverse interference signal to get the target signal.

The invention discloses an unrestrictive line voltage-following and power-buffering amplifier, and belongs to the technical field of amplifiers. The unrestrictive line voltage-following and power-buffering amplifier comprises a first control circuit and a second control circuit symmetrical to the first control circuit, wherein the first control circuit comprises a reference voltage comparing, buffering and amplifying circuit and a power buffering and amplifying circuit; the reference voltage comparing, buffering and amplifying circuit comprises a first effect tube, a third triode, a fifth triode, a first constant current source circuit for providing working currents and a first current mirror circuit for providing bias currents; the power buffering and amplifying circuit comprises a nineteenth triode, a twentieth triode, a twenty fourth triode, a twenty seventh effect tube and a second constant current source circuit for providing driving currents. When a follower works dynamically, input bias voltage and output bias voltage form a peering relationship, so that input signal voltage is approximately equal to voltage output to a load and zero distortion amplification of a signal is achieved.

The invention relates to an audio circuit and system. A relatively smooth amplitude response can be provided in a full frequency-domain audio system formed by combining two loudspeaker units, and thephase difference of a first filter unit and a second filter unit can be controlled to be in a preset phase difference range in an effective play frequency range. Accordingly, the phase difference of the tweeter loudspeaker unit and the woofer loudspeaker unit tend to zero and linearity, and then sounds of the tweeter unit and the woofer unit are integrated into one sound source. Meanwhile, the output signal quality of the second filter unit is improved by means of a speed feedback audio power amplification unit to improve the play effect of the woofer loudspeaker unit, and then the sound quality level of the full frequency-domain audio system is comprehensively increased.

The invention relates to a method for reducing the nonlinear distortion of multi-carrier signals in an LTE system. Firstly, constellation mapping and modulation are performed on the original transmission signal to obtain a multi-carrier time-domain transmission signal. By comparing the changes of the multi-carrier time-domain transmission signal through a power amplifier, the obtained The introduced noise component, and select the noise component to form the carrier injection set, and then obtain the subtracted signal in the carrier injection set, and combine it with the multi-carrier time domain transmission signal to obtain a new transmission signal, and finally send the new transmission signal that meets the distortion limit condition go out. The present invention can eliminate the nonlinear distortion introduced by the signal through the power amplifier to the greatest extent with relatively low complexity, thereby effectively improving the anti-interference and accuracy of signal transmission without reducing the bit error rate and transmission efficiency of the transmission system.