摘要:
A predistortion apparatus for compensating for a distortion arising from a non linear property in input to output characteristics of an amplifier, by processing calculation of a plurality of coefficients for a plurality of power series defining the predistortion characteristics for a plurality of power ranges, respectively, the predistortion apparatus includes: a coefficient update unit for setting and updating coefficients of the power series to provide the predistortion characteristics for the plurality of power ranges in accordance with a comparison between the input and output of the amplifier; and a determination unit for determining at least one threshold value defining the plurality of power ranges by shifting the threshold value and operating the coefficient update unit for updating the coefficients for each of the power series corresponding to each of the power ranges defined by the shifted threshold value.
摘要:
A wireless apparatus includes: an A/D converter which samples an in-phase signal component and a quadrature signal component from a quadrature-modulated signal of analog form alternately; a digital quadrature demodulation unit which applies digital quadrature demodulation to an output signal of the A/D converter and outputs an in-phase signal and a quadrature signal; and an error detection unit which, based on the in-phase and quadrature signals output from the digital quadrature demodulation unit, detects a time difference error between the sample timing of the in-phase signal component and the sample timing of the quadrature signal component.
摘要:
A predistortion apparatus for compensating for a distortion arising from a non linear property in input to output characteristics of an amplifier, by processing calculation of a plurality of coefficients for a plurality of power series defining the predistortion characteristics for a plurality of power ranges, respectively, the predistortion apparatus includes: a coefficient update unit for setting and updating coefficients of the power series to provide the predistortion characteristics for the plurality of power ranges in accordance with a comparison between the input and output of the amplifier; and a determination unit for determining at least one threshold value defining the plurality of power ranges by shifting the threshold value and operating the coefficient update unit for updating the coefficients for each of the power series corresponding to each of the power ranges defined by the shifted threshold value.
摘要:
A distortion compensation device which reduces a distortion of an amplifier which is added to an output signal of the amplifier, the distortion compensation device including: a plurality of distortion compensation coefficient storage circuits which stores a plurality of distortion compensation coefficients and outputs the distortion compensation coefficients according to an amplitude of an input signal of the amplifier, a distortion compensating processing circuit which adds the distortion compensation coefficient output from each of the plurality of distortion compensation coefficient storage circuits to the input signal of the amplifier, and a distortion compensation coefficient updating circuit which performs weighting processing on the distortion compensation coefficient output from each of the plurality of distortion compensation coefficient storage circuits to reduce the distortion compensation coefficient and which calculates an update value of the distortion compensation coefficient by using the distortion compensation coefficient which is subjected to the weighting processing.
摘要:
A distortion compensation apparatus for performing distortion compensation processing by applying the inverse properties of distortion properties of said power amplifier to a transmission signal to be input to a power amplifier, includes a plurality of distortion compensation coefficient storage units configured to store a plurality of distortion compensation coefficients used for said distortion compensation processing, an offset correction processing unit configured to subject said distortion compensation coefficient stored in each of said plurality of distortion compensation coefficient storage units to offset correction processing, and to generate distortion compensation coefficients in the case that said offset correction processing has not been performed, corresponding to said plurality of distortion compensation coefficient storage units, in a pseudo manner and a distortion compensation processing unit configured to subject said transmission signal to said distortion compensation processing based on said distortion compensation coefficients generated in a pseudo manner.
摘要:
A distortion compensation device includes: a frequency-characteristic adding unit configured to add a frequency characteristic to an error signal to generate an added error signal, the error signal being a difference between an input signal input to an amplifier and an output signal output from the amplifier; a distortion-compensation-coefficient updating unit configured to update a distortion compensation coefficient for compensating for a distortion characteristic of the amplifier based on the added error signal; and a distortion compensation unit configured to perform distortion compensation on the input signal using the updated distortion compensation coefficient.
摘要:
A predistorter includes a distortion compensating unit which gives, in advance, a reverse characteristic of a characteristic of input to output of a power amplifier to a transmission signal which is to be input to the power amplifier; a distortion compensation signal generating unit which generates a distortion compensation signal indicating the reverse characteristic based on transmission data that is sample data of the transmission signal and the delayed transmission data; and a delay amount control unit which controls a delay amount of the transmission data according to an output signal of the power amplifier.
摘要:
A transmitter, when the power changes at a certain timing, adjusts the gain for the transmission signal before the application of the distortion compensation process correspondingly to the amplitude of the transmission signal at the certain timing based on the average of the power of a transmission signal before application of the distortion compensation process, obtains a distortion compensation coefficient corresponding to the value of the power of the adjusted transmission signal from the LUT, applies the distortion compensation process to the transmission signal using the obtained distortion compensation coefficient, calculates an update for a distortion compensation coefficient corresponding to the obtained distortion compensation coefficient and stored in the LUT based on an error between the power of the transmission signal amplified by an amplifier and the power of the transmission signal before the application of the distortion compensation process, and updates the LUT using the calculated update.
摘要:
A distortion compensation apparatus for performing distortion compensation processing by applying the inverse properties of distortion properties of the power amplifier to a transmission signal to be input to a power amplifier, includes a plurality of distortion compensation coefficient storage units configured to store a plurality of distortion compensation coefficients used for the distortion compensation processing, an offset correction processing unit configured to subject the distortion compensation coefficient stored in each of the plurality of distortion compensation coefficient storage units to offset correction processing, and to generate distortion compensation coefficients in the case that the offset correction processing has not been performed, corresponding to plurality of distortion compensation coefficient storage units, in a pseudo manner and a distortion compensation processing unit configured to subject the transmission signal to the distortion compensation processing based on the distortion compensation coefficients generated in a pseudo manner.
摘要:
A distortion compensation device which reduces a distortion of an amplifier which is added to an output signal of the amplifier, the distortion compensation device including: a plurality of distortion compensation coefficient storage circuits which stores a plurality of distortion compensation coefficients and outputs the distortion compensation coefficients according to an amplitude of an input signal of the amplifier, a distortion compensating processing circuit which adds the distortion compensation coefficient output from each of the plurality of distortion compensation coefficient storage circuits to the input signal of the amplifier, and a distortion compensation coefficient updating circuit which performs weighting processing on the distortion compensation coefficient output from each of the plurality of distortion compensation coefficient storage circuits to reduce the distortion compensation coefficient and which calculates an update value of the distortion compensation coefficient by using the distortion compensation coefficient which is subjected to the weighting processing.