摘要:
A distortion compensation apparatus includes an amplifier for amplifying an input signal, a calculation unit for obtaining a distortion compensation coefficient of the amplifier corresponding to an amplitude level of the input signal, based on the input signal input to the amplifier and an output signal output from the amplifier, a memory for storing the distortion compensation coefficient, obtained by the calculation unit, into a write address being made to correspond to the input signal amplitude level, a distortion compensation processing unit for reading out the distortion compensation coefficient from the readout address of the memory, and for performing distortion compensation processing of the input signal using the distortion compensation coefficient, and an address generator for generating the write address and the readout address, based on the input signal amplitude level.
摘要:
A timing adjusting method detects a phase error between a main signal path from which a transmitting signal is obtained and a control signal path from which a voltage control signal is obtained, based on a to-be-amplified signal that is to be amplified and represents an amplitude or a power of the transmitting signal prior to amplification and a feedback signal that represents an amplitude or a power of the transmitting signal after the amplification, adjusts an amount of delay of at least one of the main signal path and the control signal path so as to mutually cancel the phase error, and amplifies the transmitting signal from the main signal path depending on the voltage control signal from the control signal path. The detecting the phase error may include detecting polarity transition points of a slope of a waveform of the to-be-amplified signal or the feedback signal, and measuring the phase error using the detected polarity transition points.
摘要:
A distortion compensation apparatus includes an amplifier for amplifying an input signal, a calculation unit for obtaining a distortion compensation coefficient of the amplifier corresponding to an amplitude level of the input signal, based on the input signal input to the amplifier and an output signal output from the amplifier, a memory for storing the distortion compensation coefficient, obtained by the calculation unit, into a write address being made to correspond to the input signal amplitude level, a distortion compensation processing unit for reading out the distortion compensation coefficient from the readout address of the memory, and for performing distortion compensation processing of the input signal using the distortion compensation coefficient, and an address generator for generating the write address and the readout address, based on the input signal amplitude level.
摘要:
A multicarrier signal transmission apparatus provided with a hard clip suppression unit for hard clipping a peak part of a multicarrier signal, a low pass filter for filtering the signal hard clipped by the hard clip suppression unit, and a peak suppression unit for suppressing the peak part of the signal after filtering by the low pass filter, the peak suppression unit provided with a peak detection unit for detecting a peak part of the filtered signal, a window function generation unit for generating a window function of an amplitude in accordance with a peak level of the peak part, and a peak suppressor for attenuating the peak part in accordance with the value of the window function.
摘要:
A timing controller is disclosed that includes: an amplifier part configured to amplify a first input signal in accordance with a control voltage, the first input signal being one of a transmission signal and a signal of a fixed value; a detector part configured to detect envelope information from the output signal of the amplifier part; a controller part configured to determine a delay difference from the transmission signal and the envelope information and transmit a timing control signal based on the delay difference; and a delay corrector part configured to correct the delay of a second input signal in accordance with the timing control signal, the second input signal being one of the transmission signal and a signal of a fixed value. One of the first and second input signals employs the corresponding signal of the fixed value in the case of correcting the delay.
摘要:
Disclosed is a phase calibration method for inserting a calibration signal (SC) into main signals (SM1 to SMn) of a plurality of branches in turn, estimating the phase characteristic of an analog circuit to which a respective one of the main signals is input and calibrating the phase of each main signal. The method includes steps of outputting a first combined signal obtained by combining output signals from the analog circuits (62a to 62n) in all branches, outputting a second combined signal obtained by combining the main signals in all branches, extracting the calibration signal by removing the second combined signal from the first combined signal in a calibration signal extracting unit (64), estimating the phase characteristics of the analog circuits, to which the main signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal, and subjecting the main signals to phase adjustment having characteristics that are opposite the phase characteristics.
摘要:
A disclosed transmission device includes a voltage control signal generating unit configured to generate a first voltage control signal from a transmission signal, an amplifier configured to amplify the transmission signal in response to the first voltage control signal, a first timing adjusting unit configured to adjust a control timing for the first voltage control signal, and a control timing setting unit configured to set the control timing adjusted by the first timing adjusting unit based on the output signal from the amplifier and the transmission signal.
摘要:
A technique wherein when signals, the modulation schemes of which are different, are to be combined, performing the peak suppression using amounts of the respective modulation schemes can effectively reduce the PAPR of a resulting combined signal. A peak suppressing method for use in a peak suppressing circuit, which combines input signals of different modulation schemes in a time domain to provide a combined signal, comprises detecting, as a peak, that portion of the combined signal which excesses a threshold value to generate a peak signal in accordance with the peak; converting the peak signal into a frequency domain signal and then dividing it into signals originating from the input signals to use these input-signal-originated signals as respective suppression signals; and adding, to the input signals, the suppression signals having different suppression amounts for the respective modulation schemes, thereby performing the peak suppression.
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.