摘要:
First, a digital section constituting a linearizer is activated. Then, a feedback loop for updating a distortion compensation coefficient is opened. Then, the analog section on the antenna side is activated from an ADC, including a PA, etc., or a DAC. Then, both the ATT value of an ATT installed in a feedback route for updating the distortion compensation coefficient and the signal delay amount of a signal delay unit are adjusted to make a state such that the distortion compensation coefficient can be accurately updated. Then, the feedback loop is closed, a distortion compensation table having the distortion compensation coefficient as an entry is generated and after the generation is completed, the operation shifts to the normal operation.
摘要:
A distortion compensation apparatus includes an amplifying unit, a plurality of distortion compensation coefficient storage units, a first address generating unit, a second address generating unit, and a distortion compensating unit. The amplifying unit amplifies an input signal. A plurality of distortion compensation coefficient storage units store the distortion compensation coefficients for compensating for the distortion of the amplifying unit by being associated with two different addresses. The first address generating unit generates a first address based on the current input signal. The second address generating unit generates a second address different from the first address based on the previous input signal. The distortion compensating unit obtains the distortion compensation coefficient corresponding to a combination of the first and second addresses from each of the distortion compensation coefficient storage units and performs a pre-distortion processing for the current input signal to the amplifying unit using the obtained distortion compensation coefficient.
摘要:
In an electronic device having a circuit outputting a vector sum of two quadrature vector signals, an offset compensating device compensates the offset contained in the vector sum. The offset compensating device aims to flexibly adapt to deviation in characteristics and performances and various fluctuations, and to compensate offset stably and accurately. The offset compensating device includes a deviation monitor unit creating a vector signal by A/D-converting the aforementioned vector sum and by quadrature-demodulating it and monitoring the deviation of the DC components superposed on the vector signal, and an adaptive control unit updating the compensation vector determined in advance, based on adaptive algorithm minimizing expectation value of the product of the inner product between an increment vector and the compensation vector, and the latest deviation vector, and adding the compensation vector to an offset vector to be inputted, while being superposed on the input signal, to a circuit.
摘要:
In an array-antenna-equipped communication apparatus, a part of a transmission signal after passing through a radio wave transmitter is branched by a directional coupler, combined by a combiner, converted to a baseband signal by a receiver for calibration, analog-converted by an analog-to-digital converter, and input to an adaptive controller as a feedback signal. The adaptive controller calculates a calibration value that minimizes the power of an error signal representing a difference between the feedback signal and a reference signal, which is the transmission signal before passing through the radio wave transmitter, and outputs the calibration value to a corrector for calibration.
摘要:
In an electronic device having a circuit outputting a vector sum of two quadrature vector signals, an offset compensating device compensates the offset contained in the vector sum. The offset compensating device aims to flexibly adapt to deviation in characteristics and performances and various fluctuations, and to compensate offset stably and accurately. The offset compensating device includes a deviation monitor unit creating a vector signal by A/D-converting the aforementioned vector sum and by quadrature-demodulating it and monitoring the deviation of the DC components superposed on the vector signal, and an adaptive control unit updating the compensation vector determined in advance, based on adaptive algorithm minimizing expectation value of the product of the inner product between an increment vector and the compensation vector, and the latest deviation vector, and adding the compensation vector to an offset vector to be inputted, while being superposed on the input signal, to a circuit.
摘要:
A distortion compensation apparatus returns a part of an amplified output signal of a power amplifier amplifying a transmission signal, reads a distortion compensation signal from a distortion compensation table, multiplies the transmission signal with the distortion compensation signal thereof, and inputs the signal to the power amplifier. The distortion compensation signal corresponding to a signal calculated based on an error signal that is a difference between the transmission signal and the amplified output signal, the distortion compensation signal from the distortion compensation table and the step size parameter, and to a power of the transmission signal. The distortion compensation apparatus comprises a &mgr; control part including a fast Fourier transformation part that obtains a spectrum of the amplified output signal, a calculation part that calculates an adjacent channel leakage power ratio based on the spectrum, and a &mgr; adjusting part that varies the step size parameter by comparing the calculated adjacent leakage power ratio with a threshold value.
摘要:
A power amplifying device includes an amplifier that amplifies a signal which is input in accordance with a voltage signal which is supplied to the amplifier, a voltage control section that controls the voltage signal in accordance with a transmission signal, a distortion compensating section that executes a distortion compensating process on the transmission signal by giving a value indicative of a reverse characteristic of the amplifier to the transmission signal in advance and inputs an output signal obtained by executing the distortion compensating process into the amplifier, an amplitude detecting section that detects an amplitude of the transmission signal, and a timing adjusting section that adjusts timings of the output signal and the voltage signal so that a value relating to the distortion compensating process meets a given condition when a detected value of the amplitude of the transmission signal is less than a given value.
摘要:
The purpose of the present invention is to compensate the distortion of an amplifier by a predistorter which compensates the distortion of a power amplifier even when a frequency amplitude deviation exists. The predistorter comprises a distortion compensation coefficient storage unit for storing a distortion compensation coefficient corresponding to the reference value using the characteristic quantity of the envelope of a transmission signal before being inputted to the power amplifier as a reference value; and a reference value conversion unit for converting the characteristic quantity into a predetermined value according to the size of the characteristic quantity, and when the characteristic quantity is, for example, the amplitude value of an envelope and the amplitude value is small, that value is rounded up, for example, to an upper-limit value within a linear range of the amplifier.
摘要:
The purpose of the present invention is to compensate the distortion of an amplifier by a predistorter which compensates the distortion of a power amplifier even when a frequency amplitude deviation exists. The predistorter comprises a distortion compensation coefficient storage unit for storing a distortion compensation coefficient corresponding to the reference value using the characteristic quantity of the envelope of a transmission signal before being inputted to the power amplifier as a reference value; and a reference value conversion unit for converting the characteristic quantity into a predetermined value according to the size of the characteristic quantity, and when the characteristic quantity is, for example, the amplitude value of an envelope and the amplitude value is small, that value is rounded up, for example, to an upper-limit value within a linear range of the amplifier.