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

The embodiments of the present invention provide a method and an apparatus for compensating nonlinear distortions in an intensity modulation-direct detection (IM-DD) system; wherein the method comprises: calculating, according to nonlinear coefficients and differences between values of an input signal at different time, nonlinear distortions of the input signal, so as to eliminate the nonlinearity distortions. By applying the method and the apparatus provided by the embodiments of the present invention, nonlinear cost of the IM-DD system can be effectively reduced, thereby improving the system capacity.

A digital reception apparatus includes a receiver that performs reception processing on a received signal and an adjuster that adjusts the amplitude of the received signal after the reception processing. A distortion estimator estimates a non-linear distortion of the received signal after the reception processing, the non-linear distortion being caused by the reception processing. A distortion corrector performs a distortion correction on the estimated non-linear distortion. A controller controls the adjuster based on a gain control signal such that the amplitude of a desired signal contained in the received signal after the reception processing and the distortion correction approaches a required level. The distortion estimator estimates the non-linear distortion of the received signal with reference to the gain control signal.

The invention provides a method for controlling gain and attenuation of a broadband low-noise amplifier. A main gain amplifier and an auxiliary gain amplifier are arranged between a radio frequency input end and an output end of the amplifier, an output end of the main gain amplifier is connected with a main adjustable attenuator, an output end of the main adjustable attenuator is connected with a multilevel radio frequency gain amplifier, the multilevel radio frequency gain amplifier is connected with the output end of the amplifier, an input end of the auxiliary gain amplifier is connected with an auxiliary adjustable attenuator, the auxiliary adjustable attenuator and the auxiliary gain amplifier are connected with the main gain amplifier in parallel, the main gain amplifier and the auxiliary gain amplifier respectively have a fixed gain value. through the on / off of the main gain amplifier and the auxiliary gain amplifier, the respective adjustment values of the main adjustable attenuator, the auxiliary adjustable attenuator and the multilevel radio frequency gain amplifier are combined at the output end of the amplifier to obtain a linear gain or attenuation value; meanwhile, the gain value and the attenuation value range are enlarged, thus the dynamic range can be greatly increased, strong interference can be restrained and nonlinear distortion can be eliminated.

A signal receiving method is used to receive a target signal, wherein the target signal is stored in a wideband signal. And the method comprises that first, receiving a wideband signal, then removing the target signal from the wideband signal to obtain an interference signal, then converting the interference signal into phase-reverse interference signal, at least, combinging the wideband signal and the phase-reverse interference signal to obtain a target signal.

Disclosed herein are a method for estimating a self-interference signal based on iterative estimation and an apparatus for the same. The method is configured to transmit two preamble signals from the transmission antenna of one terminal to the reception antenna thereof, to estimate third-order nonlinear distortion, which distorts a self-interference signal, based on a transmission signal and a reception signal for each of the two preamble signals, to update the reception signal by eliminating the third-order nonlinear distortion therefrom, to re-estimate the third-order nonlinear distortion based on the updated reception signal, and to estimate the self-interference signal based on the final third-order nonlinear distortion, which is acquired by repeatedly re-estimating the third-order nonlinear distortion as many times as a preset number of iterations.

The embodiments of the present invention provide a method and an apparatus for compensating nonlinear distortions in an intensity modulation-direct detection (IM-DD) system; wherein the method comprises: calculating, according to nonlinear coefficients and differences between values of an input signal at different time, nonlinear distortions of the input signal, so as to eliminate the nonlinearity distortions. By applying the method and the apparatus provided by the embodiments of the present invention, nonlinear cost of the IM-DD system can be effectively reduced, thereby improving the system capacity.

The invention discloses a calculation method and system of a flux linkage, applied to a stator or a rotor. The calculation method of the flux linkage comprises feed-forward integral treatment, coordinate conversion, amplitude limiting treatment and low-pass filtering treatment for an input voltage; the feed-forward integral treatment and the low-pass filtering treatment compose a double-integral link which can remove problems of nonlinear distortion and saturated drifting, realize complete compensation of an amplitude value and a phase, and enable the finally output waveform to have a good sine degree and very low distortion. In addition, adjustment of the amplitude value can be realized through the amplitude limiting processing, so that the amplitude is not greater than a preset stator or rotor flux linkage amplitude value. Therefore, the direct current offset of the output waveform can be removed efficiently.

A modular electrode water belongs to the technical field of manufacture of measuring equipment and comprises a gauge body, 74HC165 integrated chip, pull-up resistors Ru, a single-chip microcomputer, and a display; the front of the gauge body is fitted with an outer cover panel, the chip is fixed in the gauge body, each output end is connected to one pull-up resistor Ru, the output end of the chip is connected to the single-chip microcomputer, a measuring point P is made between the chip and each pull-up resistor Ru, the measuring points P are fixed to the back of the chip sequentially from top to bottom, and a wave stabilizing cavity is formed between the back of the chip and the outer cover panel. In operation, when water level is below the points P, the measuring points P are at high level; when the water level reaches the measuring points P, the measuring points P are at low level. High-precision digital measurement is provided for water level, the measurement is insusceptible to the changes in ambient temperature, humidity, noise and altitude height, the nonlinear distortion problem can be eliminated, and the data are reliable.

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 invention discloses a bass loudspeaker box, which is characterized by comprising a loudspeaker box body, an upper cover and a lower cover, wherein the front side of the loudspeaker box body is provided with a first bass unit, the top surface and the bottom surface of the loudspeaker box body are provided with an upper groove and a lower groove respectively, the upper groove and the lower groove are internally provided with a third bass unit and a second bass unit respectively, both the second bass unit and the third bass unit face towards the internal part of the loudspeaker box, the uppercover and the lower cover are respectively connected at the top and the bottom of the loudspeaker box body, a first cavity is formed between the upper cover and the upper groove, the first cavity iscommunicated with the upper groove, a second cavity is formed between the lower cover and the lower groove, the second cavity is communicated with the lower groove, and the internal part of the wholeloudspeaker box forms a closed space. The bass loudspeaker box can have an astonishing low distortion degree at an extremely low low-frequecy submergence degree, achieves an excellent speed by explosive unit motion and can eliminate the phenomena of nonlinear distortion and dynamic shortage caused by swinging and shifting of a vibration basin when only one bass unit is adopted.

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 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 discloses a bass loudspeaker box, which is characterized by comprising a loudspeaker box body, an upper cover and a lower cover, wherein the front side of the loudspeaker box body is provided with a first bass unit, the top surface and the bottom surface of the loudspeaker box body are provided with an upper groove and a lower groove respectively, the upper groove and the lower groove are internally provided with a third bass unit and a second bass unit respectively, both the second bass unit and the third bass unit face towards the internal part of the loudspeaker box, the uppercover and the lower cover are respectively connected at the top and the bottom of the loudspeaker box body, a first cavity is formed between the upper cover and the upper groove, the first cavity iscommunicated with the upper groove, a second cavity is formed between the lower cover and the lower groove, the second cavity is communicated with the lower groove, and the internal part of the wholeloudspeaker box forms a closed space. The bass loudspeaker box can have an astonishing low distortion degree at an extremely low low-frequecy submergence degree, achieves an excellent speed by explosive unit motion and can eliminate the phenomena of nonlinear distortion and dynamic shortage caused by swinging and shifting of a vibration basin when only one bass unit is adopted.

Disclosed herein are a method for estimating a self-interference signal based on iterative estimation and an apparatus for the same. The method is configured to transmit two preamble signals from the transmission antenna of one terminal to the reception antenna thereof, to estimate third-order nonlinear distortion, which distorts a self-interference signal, based on a transmission signal and a reception signal for each of the two preamble signals, to update the reception signal by eliminating the third-order nonlinear distortion therefrom, to re-estimate the third-order nonlinear distortion based on the updated reception signal, and to estimate the self-interference signal based on the final third-order nonlinear distortion, which is acquired by repeatedly re-estimating the third-order nonlinear distortion as many times as a preset number of iterations.

The invention discloses an optical transmission method and device based on power spectrum shaping, which supports direct detection of optical signals with high spectral efficiency, that is, square demodulation. The present invention adopts the power spectrum shaping modulation method at the sending end, and the modulation method is passed at the zero point, that is, V π Bias the Mazeng optical modulator, increase the level, combine with nonlinear precoding, realize multi-level improved duobinary coding and multi-level biased duobinary coding, and also combine optical filters to realize vestigial sideband improved duobinary coding; At the receiving end, nonlinear equalization is used to remove intersymbol interference from the received signal, and at the same time, the difference in received level can be fed back to the transmitter to realize non-equidistant multi-level modulation and reduce the complexity of nonlinear equalization. The present invention enables direct detection of signals requiring coherent demodulation through proper nonlinear precoding and nonlinear equalization, thereby reducing hardware complexity.

A method for avoiding spurious emissions in an AM transmitter for digital transmission includes converting a digital modulation for controlling the AM transmitter into an amplitude signal for an amplitude branch, and a phase-modulated RF signal for a RF branch. Non-linear distortions in an amplitude response and a delay-time characteristic of an amplitude branch are compensated for using a pre-equalization with inverse shapes by measuring and storing the amplitude response and the delay-time characteristic of the RF branch. An inverse transfer function is determined using respective shapes of the measured amplitude response and delay-time characteristic by an inverse Fourier transform. An equalizing network is dimensioned for the determined inverse transfer function. The equalizing network is connected in series upstream of the RF branch. The amplitude and RF branches are combined downstream of the amplitude and RF branches.

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.