Amplifying device and method for controlling the same

A control device for a power amplifier comprising a power supply voltage modulation unit modulating a power supply voltage, comprising:

• a first pre-distorter unit outputting, to the power amplifier, a modulated signal obtained by adding a phase compensation amount and an amplitude adjustment amount to an input signal;
• a second pre-distorter unit controlling the power supply voltage modulation unit on the basis of amplitude information on the input signal;
• and
• a control unit controlling an operation of the first pre-distorter unit and the second pre-distorter unit;
• wherein the control unit comprises
• a phase control unit controlling the phase compensation amount by using a phase coefficient,
• a first amplitude control unit controlling the amplitude adjustment amount by using a first amplitude coefficient, and
• a second amplitude control unit controlling the operation of the second pre-distorter unit by using a second amplitude coefficient;
• and
• wherein the first amplitude control unit cooperates with the second amplitude control unit so that an amplitude amplification factor may become constant which is a ratio of an amplitude of an output signal of the power amplifier to an amplitude of the input signal.

A method for controlling an amplifying device, comprising the steps of:

• updating a phase coefficient determining a phase compensation amount to an input signal of an amplifying device so that a phase difference between the input signal and an output signal of the amplifying device may be minimized;
• calculating a phase correction value which is a phase coefficient to minimize the phase difference;
• generating an input modulated signal by applying to the input signal a function whose output value is equal to or greater than an input value for every input value;
• updating a first amplitude coefficient determining an amplitude adjustment amount to the input signal so that an amplitude difference between the input modulated signal and the output signal may be minimized;
• calculating a first amplitude correction value which is the first amplitude coefficient to minimize an amplitude difference between the input modulated signal and the output signal;
• updating a second amplitude coefficient determining an amplitude of a power supply voltage of a power amplifier composing the amplifying device, under the condition that the first amplitude correction value is kept constant, on the basis of amplitude information on the input signal so as to supply a power supply voltage by which an output of the power amplifier becomes a saturated state;
• calculating, as a second amplitude correction value, the second amplitude coefficient at a time when an amplitude amplification factor becomes constant which is the ratio of an amplitude of the output signal to an amplitude of the input signal;
• and
• compensating phase difference between the input signal and the output signal by using the phase correction value and controlling the amplitude amplification factor to be kept constant by using the first amplitude correction value and the second amplitude correction value.

A non-transitory computer-readable recording medium storing a program which makes a computer execute a procedure for updating a phase coefficient determining a phase compensation amount to an input signal of an amplifying device so that a phase difference between the input signal and an output signal of the amplifying device may be minimized;

• a procedure for calculating a phase correction value which is a phase coefficient to minimize the phase difference;
• a procedure for generating an input modulated signal by applying to the input signal a function whose output value is equal to or greater than an input value for every input value;
• a procedure for updating a first amplitude coefficient determining an amplitude adjustment amount to the input signal so that an amplitude difference between the input modulated signal and the output signal may be minimized;
• a procedure for calculating a first amplitude correction value which is the first amplitude coefficient to minimize an amplitude difference between the input modulated signal and the output signal;
• a procedure for updating a second amplitude coefficient determining an amplitude of a power supply voltage of a power amplifier composing the amplifying device, under the condition that the first amplitude correction value is kept constant, on the basis of amplitude information on the input signal so as to supply a power supply voltage by which an output of the power amplifier becomes a saturated state;
• a procedure for calculating, as a second amplitude correction value, the second amplitude coefficient at a time when an amplitude amplification factor becomes constant which is the ratio of an amplitude of the output signal to an amplitude of the input signal;
• and
• a procedure for compensating phase difference between the input signal and the output signal by using the phase correction value and controlling the amplitude amplification factor to be kept constant by using the first amplitude correction value and the second amplitude correction value.