A device configured to perform wireless communication includes: a pre-distortion circuit configured to generate a pre-distorted input signal by performing pre-distortion on an input signal based on a parameter set comprising a plurality of coefficients; a power amplifier configured to generate an output signal by amplifying an RF signal based on the pre-distorted input signal; and a parameter obtaining circuit configured to obtain second memory polynomial modeling information corresponding to an operating frequency band based on first memory polynomial modeling information corresponding to each of a plurality of frequency sections and obtain a parameter set according to an indirect learning structure by using the second memory polynomial modeling information.

Optimally detuned parametric amplification amplifies a signal in a resonator that is driven off-resonance, with respect to a signal mode, using a far-detuned pump. This pump establishes a parametric drive strength, and is “far-detuned” in that its detuning from the signal mode is greater than the drive strength. The amplitude and frequency of the pump are chosen so that the eigenfrequency of the resulting Bogoliobov mode matches a photonic loss rate of the Bogoliobov mode. In this case, a signal coupled into the Bogoliobov mode will be amplified with a gain that is broader and flatter than that achieved with conventional parametric amplification, and is not limited by a gain-bandwidth product. Optimally detuned parametric amplification may be used for degenerate or non-degenerate parametric amplification, and may be used to amplify microwaves, light, electronic signals, acoustic waves, or any other type of signal that can be amplified using conventional parametric amplification.

Optimally detuned parametric amplification amplifies a signal in a resonator that is driven off-resonance, with respect to a signal mode, using a far-detuned pump. This pump establishes a parametric drive strength, and is “far-detuned” in that its detuning from the signal mode is greater than the drive strength. The amplitude and frequency of the pump are chosen so that the eigenfrequency of the resulting Bogoliobov mode matches a photonic loss rate of the Bogoliobov mode. In this case, a signal coupled into the Bogoliobov mode will be amplified with a gain that is broader and flatter than that achieved with conventional parametric amplification, and is not limited by a gain-bandwidth product. Optimally detuned parametric amplification may be used for degenerate or non-degenerate parametric amplification, and may be used to amplify microwaves, light, electronic signals, acoustic waves, or any other type of signal that can be amplified using conventional parametric amplification.

A Doherty amplifier (10) according to the present invention includes: a distribution unit (11) that distributes input signals; a main amplifier (12) that amplifies a first distributed signal output from the distribution unit (11); a transmission line unit (13) that transmits the first distributed signal amplified by the main amplifier (12); a peak amplifier (14) that amplifies a second distributed signal output from the distribution unit (11); a transmission line unit (15) that transmits the second distributed signal amplified by the peak amplifier (14); a synthesizing unit (16) that synthesizes the first distributed signal and the second distributed signal, and outputs a synthesized signal; and an impedance transformation unit (17) that performs an impedance transformation of the synthesized signal output from the synthesizing unit (16). The impedance transformation unit (17) includes a plurality of λ/4 transmission lines connected in series.

A Doherty amplifier (10) according to the present invention includes: a distribution unit (11) that distributes input signals; a main amplifier (12) that amplifies a first distributed signal output from the distribution unit (11); a transmission line unit (13) that transmits the first distributed signal amplified by the main amplifier (12); a peak amplifier (14) that amplifies a second distributed signal output from the distribution unit (11); a transmission line unit (15) that transmits the second distributed signal amplified by the peak amplifier (14); a synthesizing unit (16) that synthesizes the first distributed signal and the second distributed signal, and outputs a synthesized signal; and an impedance transformation unit (17) that performs an impedance transformation of the synthesized signal output from the synthesizing unit (16). The impedance transformation unit (17) includes a plurality of λ/4 transmission lines connected in series.

Provided is a variable filter circuit that can control the bandwidth and center frequency of a pass band, can realize steep attenuation characteristics in bands close to the pass band, and enables the total number of variable reactance units to be reduced. A variable filter circuit includes an inductor (Ls1) and a capacitor (Cs1), which are connected in series between a first input/output terminal (P1) and a second input/output terminal (P2), and resonators (Re_p1, Re_p2, Re_p3, Re_p4) and variable capacitors (Cc1, Cc2, Cc3, Cc4), which are connected in series between two ends of the inductor (Ls1) and the capacitor (Cs1) and ground connection terminals.

A wideband self-envelope tracking power amplifier (PA) can use more than a 40-MHz channel bandwidth and improves the envelope bandwidth limit of a self-envelope tracking PAs by ten times. The PA uses an envelope load network, which is based on a general multi-stage low-pass filter. The envelope load network located between an RF choke inductor and main DC power supply provides a dynamically modulated PA supply voltage without using a dedicated envelope amplifier. An input terminal of the network connects a main PA via an RF choke inductor to an input of low-pass filter. An output terminal is connected to the low-pass filter via an envelope choke inductor and to a direct current (DC) power supply. A DC blocker is connected between the output of the low-pass filter and ground by a termination resistor.

A wideband self-envelope tracking power amplifier (PA) can use more than a 40-MHz channel bandwidth and improves the envelope bandwidth limit of a self-envelope tracking PAs by ten times. The PA uses an envelope load network, which is based on a general multi-stage low-pass filter. The envelope load network located between an RF choke inductor and main DC power supply provides a dynamically modulated PA supply voltage without using a dedicated envelope amplifier. An input terminal of the network connects a main PA via an RF choke inductor to an input of low-pass filter. An output terminal is connected to the low-pass filter via an envelope choke inductor and to a direct current (DC) power supply. A DC blocker is connected between the output of the low-pass filter and ground by a termination resistor.

A wideband RF choke circuit includes an input, first and second nodes, and a splitting means coupled between the input, first node, and second node. A first all-pass filter and a first line AC blocker are coupled between the input and the splitting means. Second and third all-pass filters, and second and third line AC blockers, are coupled between the splitting means and the first and second nodes, respectively. A first RF choke has a first end, coupled to the first all-pass filter, and a second end. A second RF choke has a first end, coupled to the second end of the first RF choke, and a second end coupled to the second all-pass filter. A third RF choke has a first end, coupled to the second end of the first RF choke, and a second end coupled to the third all-pass filter.

A wideband RF choke circuit includes an input, first and second nodes, and a splitting means coupled between the input, first node, and second node. A first all-pass filter and a first line AC blocker are coupled between the input and the splitting means. Second and third all-pass filters, and second and third line AC blockers, are coupled between the splitting means and the first and second nodes, respectively. A first RF choke has a first end, coupled to the first all-pass filter, and a second end. A second RF choke has a first end, coupled to the second end of the first RF choke, and a second end coupled to the second all-pass filter. A third RF choke has a first end, coupled to the second end of the first RF choke, and a second end coupled to the third all-pass filter.