Abstract:
An amplitude frequency characteristic adjustment circuit 106 is provided downstream of and connected to a distortion generation circuit 105. An amplitude difference between low-frequency-side and high-frequency-side distortion voltages is adjusted by the amplitude frequency characteristic adjustment circuit 106, and then their amplitudes and phases are adjusted by a vector adjustment circuit 107. This configuration makes it possible to suppress simultaneously both of low-frequency-side and high-frequency-side distortion voltages of a distortion generated by a wide-band class-AB power amplifier even if they are different in amplitude and phase.
Abstract:
Provided is a distortion-compensated amplifying circuit capable of suppressing distortion without attenuating a level of carrier components, and further obtaining a larger amount of suppression of distortion, which has not been achievable by conventional distortion-compensated amplifying circuit using a pre-distortion technique. A balanced type amplifying circuit is structured such that amplifiers 115 and 116 placed in parallel are sandwiched by 90-degree hybrid circuits 114 and 117. The 90-degree hybrid circuit 114 is supplied with an original signal including carrier components and a distortion signal including distortion equal in amplitude and opposite in phase (having a phase difference of 180 degrees) to distortion that occurs when the original signal is amplified by the amplifiers 115 and 116. The 90-degree hybrid circuit 114 performs a process of differential amplification with a phase difference of 180 degrees between the original signal and the distortion signal. Then, the amplified original signal and distortion signal outputted from the 90-degree hybrid circuit 117 are combined by a directional coupler 118, thereby canceling distortion components included in both signals with each other.
Abstract:
A balun design incorporating the functions of a splitter (combiner) which can be employed in a high power amplifier circuit configuration. The balun is formed of a dielectric multilayer board with conductor patterns on each conductor pattern layer. The balun includes the propagation of a half of an input signal to an in-phase output terminal, and also propagating a fourth of the input signal to first and second opposite-phase output terminals, the signal propagated to the first and second opposite-phase output terminals lagging 180 degrees behind the signal propagated to the in-phase output terminal. The balun provides the output signals at the first and second opposite-phase output terminals 180° out of phase employing through holes in the main line and coupling lines for promoting electromagnetic coupling therebetween.
Abstract:
A Time Division Multiple Access FDD/TDD dual mode system includes a switch having first and second common terminals and first and second terminals. Also included are a TDD demodulation circuit for demodulating a TDD received signal from the first common terminal; a FDD demodulation circuit for demodulating a FDD received signal; and a FDD/TDD modulation circuit for modulating and impressing the modulated signal onto the second common terminal. A FDD transmission band selection circuit is connected to the first terminal, and a TDD transmission-reception band selection circuit is connected to the second terminal. The first common terminal of the switch is connected to the second terminal during TDD reception, whereas the second common terminal is connected to the first terminal during FDD transmission and to the second terminal during TDD transmission.
Abstract:
A power amplifier has an input signal splitting part for splitting the input signal into two output signals each having equal power and phase difference of 180 degrees with respect to each other. A first signal on-off selection part for switching conduction of one of the output signals. A first amplifying part for amplifying the signal from the first signal on-off selection part. A second signal on-off selection part for switching conduction of the signal outputted from the first amplifying part. A second amplifying part for amplifying the other of the output signals from the input signal splitting part. An output signal combining part for providing a phase difference of 180 degrees between the output of the second signal on-off selection part and the output of the second amplifying part and combining them. A bias on-off part for switching on and off at least the first amplifying part, wherein, when the output level is high, the first and second signal on-off selection parts are turned on and, at the same time, the first and second amplifying parts are turned on by the bias on-off part, so that push-pull operation is performed, and when the output level is low, the first and second signal on-off selection parts are turned off and the first amplifying part is turned off by the bias on-off part and the second amplifying part performs single-ended operation.
Abstract:
Disclosed is a transmitter for switching and transmitting signals of plural frequency bands. For example, the signals of two frequency bands are switched and transmitted. For the transmission in a first frequency band, of transistors 104, 105 are turned off, whereby a power amplifying transistor 102 is matched by an input wide band matching circuit 101 and an output main matching circuit 103, so that the high efficiency linear amplification is accomplished. For the transmission in a second frequency band, the transistor 104 is turned on while the transistor 105 is turned off, whereby the power amplifying transistor 102 is matched by a capacitance 108 as well as the input wide band matching circuit 101 and the output main matching circuit 103, so that the high efficiency linear amplification is accomplished. An external switch for switching the matching circuits is thus unnecessary.
Abstract:
A receiving mixer device for a mobile radio transceiver which operates with multiple modulation modes and within multiple frequency bands. The receiving mixer includes a plurality of mixers each for converting a received radio frequency signal to an intermediate frequency, a common connection part to which output terminals of the mixers are connected in common, a plurality of impedance conversion circuits connected to the common connection part, and output terminals for the impedance conversion circuits. The number of mixers is equal to the number of frequency bands of the received radio frequency signal. The number of the intermediate frequencies is equal to the number of modulation modes of the received radio frequency signal. The number of the impedance conversion circuits is equal to the number of intermediate frequencies, and each of the impedance conversion circuits passes only a single predetermined frequency of the intermediate frequencies used by the device.
Abstract:
A dual band oscillator circuit according to the present invention comprises an oscillator circuit portion that oscillates at a first frequency, an oscillator circuit portion that oscillates at a second frequency, a buffer amplifier circuit portion to which an output of the first oscillator circuit portion is input through a first stage-to-stage coupling element and an output of the second oscillator circuit portion is input through a second stage-to-stage coupling element. Operation is switched between the first and second oscillator circuits by an externally applied control voltage signal.
Abstract:
A transmitter circuit includes a first synthesizer section, and a second synthesizer section which consumes less current than the first synthesizer section. The transmitter circuit performs switching such that the first synthesizer section is operated and the second synthesizer section is powered off in polar modulation, and the second synthesizer section is operated and the first synthesizer section is powered off in quadrature modulation, thereby reducing consumed power. While the first synthesizer section is operating, calibration for an oscillation frequency is performed, and when the operation is stopped, a calibration value is stored. When an operation of the first synthesizer section is restarted, the stored calibration value is corrected by using temperature change, thereby enhancing calibration accuracy and preventing degradation in quality of a transmission signal.
Abstract:
The polar modulation apparatus of the present invention can control the output power of a transmission signal over a wide range and compensate characteristic degradation reliably upon temperature change. Polar modulation transmission apparatus 100 is provided with: temperature sensor 120; temperature compensation section 160-1 that corrects an amplitude signal and performs temperature compensation for transmission power amplification section 190; temperature compensation section 160-2 that corrects a power amplification signal and performs temperature compensation for power adjustment section 180; and correction value setting section 130 that sets correction values for temperature compensation section 160-1 and temperature compensation section 160-2, and, while only the amplitude signal is corrected according to a measurement result in temperature sensor 120 in the first mode, the amplitude signal and the power adjustment signal are corrected according to a measurement result in the second mode.