38results about How to "Improve linearization performance" patented technology

The invention relates to a method and system for wideband digital pre-distortion linearization, which is used to overcome the influence of memory effect in radio frequency power amplifier, to expand digital pre-distortion linearization bandwidth, and to improve digital pre-distortion linearization performance. The method and system can get an in-band pre-distortion signal and an out-of-band pre-distortion signal according to the characteristic parameter of the amplifier; the in-band pre-distortion signal is up-converted and the up-converted signal is added to the out-of-band pre-distortion signal, which is not up-converted, then the combined signal is inputted to the power amplifier as an input signal; a part of the output signal from the power amplifier, serving as a feedback signal, can be compared with the original input signal, and the characteristic parameter of the amplifier for generating the in-band pre-distortion signal and the out-of-band pre-distortion signal is adaptively regulated according to the comparison result, so that the waveform of time domain or the frequency domain of the feedback signal can be close to that of the original input signal as much as possible.

A method an apparatus improve linearization performance and reduce a convergence time of a Digital Pre-Distorter of a power amplifier. An input signal is received. A peak level of the input signal is expanded based on an expansion threshold. And the expanded peak level of the input signal is linearized through Digital Pre-Distorter (DPD) training on the expanded input signal.

The present invention discloses a method and a system for out-of-band predistortion linearization, comprising steps of: dividing base band inputted or intermediate frequency signal into an in-band signal branch and an out-of-band signal branch; processing the in-band signal to form RF (Radio Frequency) signal; processing the out-of-band signal to form out-of-band predistortion signal for pre-compensating the in-band signal; adding the in-band signal with the out-of-band predistortion signal, and taking the result as the input of RF power amplifier. The present invention compensates the nonlinear distortion of the RF power amplifier by a way of out-of-band compensating signal in a wireless communication environment, thereby avoiding the limitation of improving performance of conventional predistortion method, and solving the limitation of bandwidth and capability of the predistortion system caused by memory effect.

The invention provides a mixed double-frequency digital pre-distortion model method based on the DDR. The method includes the following steps that a concurrent double-frequency DPD system based on indirect learning is built; an operation sequence is optimized, a one-dimensional LUT achievement model of the 2D-MP is obtained, a one-dimensional LUT achievement model of 2D-MMP is derived, and then aone-dimensional LUT high-frequency concurrent double-frequency DPD achievement scheme and a model are provided; a dynamic deviation function is substituted into a one-order model of the DDR, and a discrete equivalent baseband expression of the one-order DDR model is obtained and extended to be in a synchronic double-frequency mode; a two-dimensional memory polynomial model same-order envelope cross term is introduced, and a new model and a one-dimensional LUT achievement method of the model in an FPGA are obtained. According to the method, the modeling accuracy and the linearization performance better than a simplified two-dimensional memory polynomial model and a traditional DDR model can be obtained; meanwhile, the advantage that achievement can be conveniently conducted through a one-dimensional lookup table is kept, the new model has a good level in the aspects of performance and complexity, and the method is suitable for practical system applying.

A method and an apparatus for determining validity of samples for a digital pre-distortion apparatus is disclosed. It is an object of at least one embodiment to provide a method and an apparatus for determining validity of samples for a digital pre-distortion apparatus that is configured to compensate for nonlinearity of a power amplifier in an efficient manner by accurately estimating a pre-distortion coefficient with a low-capacity memory.

The invention discloses a method and device for eliminating clock jitter in analog-to-digital conversion and a digital pre-distortion method and relates to the pre-distortion technology in the communication field. The method for eliminating clock jitter in analog-to-digital conversion is characterized by comprising the steps that step 1, an analog signal z (t) is received; step 2, a clock signal h (t) is offered to an analog-to-digital conversion module, meanwhile, an arithmetic product of the clock signal h (t) and a single-tone signal m (t) serves as a reference signal q (t) and is added to the analog signal z (t), so that a composite signal r (t) is obtained; step 3, analog-to-digital conversion is conducted on the composite signal r (t) through the analog-to-digital conversion module, so that two completely identical composite signals rjit (n) are obtained; step 4, after a jitter sequence of one of the two composite signals rjit (n) is estimated, a clock jitter sequence is obtained; step 5, clock jitter elimination is conducted on the other of the two composite signals rjit (n) through clock jitter sequence, so that a purified digital signal y (n) with clock jitter eliminated is obtained.

A universal and output-adjustable thermistor linear compensation circuit based on an audion comprises a sensing adjustment module, a voltage constant module, a feedback amplification module, a linear compensation circuit and an output amplification module, wherein an output end of the sensing adjustment module is connected with the input end of the feedback amplification module, the output end of the feedback amplification module is connected with the input end of the output amplification module, the output end of the output amplification module is connected with a port 1 of the linear compensation module, an output port 2 of the linear compensation module is connected with the input end of the feedback amplification module, and the input end of the linear compensation module is connected with the output end of the voltage constant module. The universal and output-adjustable thermistor linear compensation circuit based on the audion has the advantages that the linear effect of the circuit is good, the circuit is simple in structure, the conversion flexibility of the circuit is high, and large-scale production is facilitated.

In order to linearize the digital signal, two different signals are fed into the correction loop of the feedforward amplifier. One of the signals (the main signal) is pre-distorted and frequency-characteristically compensated before it is sent to the nonlinear amplifier (3). The second signal remains undistorted and is used as a reference signal, which is used to cancel out the main signal portion. These two signals are fed into a correction loop for a highly linearized output signal.

The invention discloses a reconfigurable digital pre-distortion system of a millimeter wave broadband power amplifier. The reconfigurable digital pre-distortion system comprises a digital pre-distortion model, a power amplifier, an analog tape limit filter and a model coefficient extraction module, the digital pre-distortion model generates an output signal of the digital pre-distortion model viaan original baseband input signal, the output signal of the digital pre-distortion model is sent to the power amplifier and the model coefficient extraction module, a small part of the signal obtainedby processing the output signal of the power amplifier is also transmitted back to the model coefficient extraction module, and the model coefficient extraction module extracts a digital pre-distortion model coefficient and sends the same to the digital pre-distortion model. The invention further discloses a pre-distortion method using the system. The reconfigurable digital pre-distortion systemcan flexibly select the subcarriers according to demands so as to save spectrum resources; the processing bandwidth necessary for the traditional digital pre-distortion technology is reduced; and thepressure of the existing digital signal processing chip for the high-rate data is reduced.

A multi-band signal is generated by combining two or more input signals separated in frequency. The input signals are combined either before or after predistortion depending on the bandwidth of the multi-band signal. If the bandwidth of the multi-band signal is less than a predetermined bandwidth threshold, the input signals are combined and predistortion is applied to the combined signal to generate the multi-band signal. If the bandwidth of the multi-band signal is greater than the bandwidth threshold, the individual input signals are predistorted and subsequently combined to generate the multi-band signal.

A method for raising linearity of feed forward power amplifier by utilizing carrier leakage effect includes finding out loop convergent initial adapting point to make both counterbalance loops of carrier wave and error be convergent state , searching convergent point of carrier wave leakage effect , adjusting parameters of carrier wave loop and error counterbalance loop to let carrier wave counterbalance loop leak out carrier wave energy and to let error counterbalance loop output inter-modulation signal with minimum power value .

The invention discloses a nonlinear correction system for a bridge sensor. The nonlinear correction system comprises a piezoresistive bridge sensor, a negative feedback circuit and an output gain amplifier, a negative feedback circuit is introduced to change the excitation voltage of the piezoresistive bridge type sensor and change the amplification factor of an output gain amplifier, so that an original bridge type nonlinear system is compensated; the negative feedback circuit comprises a summation module, a linearization digital-to-analog converter and a feedback amplifier which are connected in sequence, and the feedback voltage is applied to the feedback amplifier; the input end of the summation module receives feedback voltage amplified and converted by a feedback amplifier and a linearization digital-to-analog converter and reference voltage attenuated by an excitation coefficient respectively; excitation voltage output by the summation module is applied to the piezoresistive bridge type sensor. According to the invention, the nonlinear correction system is utilized to compensate the nonlinear characteristic of the piezoresistive bridge sensor, the nonlinear error can be reduced by 50 times, and a good linearization effect is achieved.

The invention mainly discloses a multilevel centralized parameter power distribution circuit for a frequency modulation frequency band, which can greatly reduce the excessive large distribution circuit area of the frequency modulation frequency band due to the wavelength problem, improve distribution balance, reduce circuit insertion loss and is particularly applicable to high power distributionand multi-antenna distribution circuits in the frequency modulation frequency band. The method is mainly characterized in that the whole circuit is composed of mutual inductance coils, coupling capacitors between self-inductance coils and terminals distributed symmetrically and grounding capacitors; and the whole circuit is small in size and compact in structure without any additional loss causedby other magnetic and other loss devices. The method is further specifically characterized in that the circuit is extended to be composed of a two-level twisted mutual inductance coil, a two-level self-inductance coil, a distributed end-to-end coupling capacitor and a to-ground coupling capacitor on the basis of a single-level twisted mutual inductance coil and a single-level self-inductance coil. The mode can greatly improve the radio frequency bandwidth and greatly reduce the insertion loss.

The disclosed circuit includes DC isolated capacitor, high frequency choking winding, decoupling capacitor and radio frequency power amplifier. Being passed through DC isolated capacitor, the input signal in radio frequency is output to the input end of the radio frequency power amplifier. The circuit also includes an operational amplifier with high input impedance. A DC bias signal is input to the positive input end of the operational amplifier. Being cascaded to the DC isolated capacitor, envelope signal is connected to negative input end of the operational amplifier. Being cascaded to high frequency choking winding, output end of the operational amplifier is connected to input end of the radio frequency power amplifier, output signal of which is the output of the disclosed circuit. The invention isolates envelope signal in low frequency from DC signal, expands applicable area of frequency suitable to linearization method of envelope injection, and lowers cost of system greatly.

The invention mainly discloses a cancellation circuit of an electric memory effect of a power amplifier. The method is specifically characterized in that an inductor is added on a transmission electrode of a transistor (or a field-effect tube), a capacitor is added between a base electrode and a collector (or a grid electrode and a drain electrode) of the transistor (or the field-effect tube), wherein the added inductor imports positive voltage feedback, and the capacitor imports negative voltage feedback, so that the depth of the positive feedback or the negative feedback can be changed by adjusting the value of the inductor or the capacitor. When the inductor or the capacitor is a certain fixed value, the fluctuation range of the base electrode impedance of the transistor or the grid electrode impedance of the field-effect tube within the working frequency range is minimum, and at this time, the improvement effect of the electric memory effect of the power amplifier is optimal.

The invention discloses an intelligent scene-oriented continuous learning digital pre-distortion system and method. The system comprises a configuration adjustment module, a continuous learning digital pre-distortion module, a linearity check module, a training data storage module, a model coefficient extraction module and a target function module. The configuration adjusting module changes configuration of an input signal in real time, the input signal obtains a pre-distortion signal through continuous learning of the digital pre-distortion module, the pre-distortion signal is transmitted to the power amplifier to obtain an output signal, the feedback loop collects the output signal, and the output signal enters the linearity checking module to check the linearity. According to the method, the model coefficient updating requirement of the digital pre-distortion technology in an intelligent scene can be greatly reduced, so that the application cost of the digital pre-distortion technology is reduced.

Circuits, controllers, and techniques are provided for reducing non-linearities in a phase rotator. A circuit, according to one implementation, includes a single Phase-Locked Loop (PLL) circuit having a main path and a return path forming a feedback loop. The circuit also includes one or more phase rotators connected to an output of the single PLL circuit outside the feedback loop and one or more adaptable Look-Up Tables (LUTs) populated with operating code to be provided to the one or more phase rotators for defining operating characteristics of the one or more phase rotators. Furthermore, the circuit includes a control device configured to receive phase response characteristics from the one or more phase rotators. The control device is further configured to modify the operating code of the one or more adaptable LUTs based on the phase response characteristics to reduce non-linearities of the one or more phase rotators.

The invention discloses a digital pre-distortion system of a dual-band analog multi-beam millimeter wave transmitter. The system comprises a dual-band multi-beam digital pre-distortion module, a transmitting link, an amplifier, an analog beam forming network, a dual-band digital pre-distortion parameter extraction module and a multi-beam digital pre-distortion parameter extraction module; the dual-band multi-beam digital pre-distortion module is composed of a multi-beam digital pre-distortion module and K dual-band digital pre-distortion modules; multi-beam crosstalk in the system can be effectively processed through multi-beam digital pre-distortion, and dual-band crosstalk and inherent nonlinearity of the power amplifier can be effectively processed through dual-band digital pre-distortion. The invention further discloses a pre-distortion method of the dual-band analog multi-beam millimeter wave transmitter. According to the invention, the problems of multi-beam crosstalk, dual-bandcrosstalk and nonlinearity of the power amplifier can be effectively solved.