Abstract: A wireless transmission apparatus of multi-mode operation with superior power efficiency is provided. Switches (115 and 117) are switched over in such a manner that a modulation signal outputted from a wireless GSM/EDGE (UB) signal formation circuit (101-3) of a high-frequency signal processing circuit (101) is outputted to a high-frequency power amplifier (104) at the time of output of a GSM modulation signal, and is outputted to a high-frequency amplifier (105) at the time of output of an EDGE modulation signal. As a result, the EDGE modulation signal is power amplified using a high-frequency power amplifier (105) for an UMTS modulation signal use that is compatible with regards to the EDGE modulation signal and the maximum output power and presence or absence of envelope fluctuation. It is therefore possible to amplify the EDGE modulation scheme wireless signal with high efficiency.

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: An amplifier includes a modulation coder receiving an original modulation signal and generating an amplitude signal and a phase signal, a voltage adjusting instrument which generates an amplitude modulation signal from the amplitude signal, a carrier generator generating a phase modulation signal from the phase signal, and an amplification device receiving the phase modulation signal and the amplitude modulation signal serving as a bias voltage and outputting a modulation signal obtained by restoring and amplifying the original modulation signal. The voltage adjusting instrument determines a DC offset voltage on the basis of a level control signal indicating the level of the amplitude modulation signal and generates the amplitude modulation signal to which the DC offset voltage is added.

Abstract: To provide a dual-polarization receiver in a hot standby transmission scheme using dual polarized wave signal transmission that has high frequency-utilizing-efficiency. A dual-polarization receiver for receiving polarized wave signals whose directions are different from each other has receiving demodulation units of a working system and a backup system for one of the polarized wave signals, and receiving demodulation units of a working system and a backup system for the other of the polarized wave signals. RF local oscillation circuits of frequency converting circuits of the working system are connected with a common REF oscillation circuit and RF local oscillation circuits of frequency converting circuits of the backup system are connected with a common REF oscillation circuit.

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: 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: 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: A power amplifier of amplifying signals of two frequency bands is reduced in size and improved in efficiency at low output. The power amplifier includes an input terminal, a branch circuit and so on having one input and a plurality of outputs, the input being connected to the input terminal, amplifying means which are connected to some outputs of the branch circuit and so on and are operated at different signal frequencies from each other, a transmission line connected to one of the other outputs of the branch circuit, a synthesizing circuit connected to the outputs of the amplifying means and the output from the transmission line, a switch provided between the transmission line and a synthesis output unit, and a control circuit of controlling conduction of the branch circuit and so on, conduction and an amplifying operation of the amplifying means, and conduction of the switch.

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: 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: 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: The present invention aims to provide a transmitter circuit that is capable of suppressing quantization noise and operating with a high efficiency, a data converter section 13 and a data conversion method for use therein, and a communications device using the same. The data converter section 13 of the present invention performs a predetermined data conversion operation on an input signal. The data converter section 13 includes: a signal processing section 133 for discretizing the input signal to produce a signal having a lower resolution magnitude-wise than that of the input signal; a subtractor section 134 for subtracting the input signal from the signal having a lower resolution to extract quantization noise; a filter 135 for extracting quantization noise near an intended wave frequency; and a subtractor section 136 for removing the quantization noise near the intended wave frequency from the signal having a lower resolution.

Abstract: The data from the orthogonal data generator is quantized by the vector data converter so as to become, for example, a binary value of 0 and a real number in magnitude. The output of the vector converter is modulated by the modulator, and is inputted to the amplifier. In the amplifier, the envelope of the signal to be inputted is quantized. That is, the signal of a constant envelope becomes a signal which is turned ON and OFF, so that a highly efficient nonlinear amplifier can be used. The quantization noise generated in the vector data converter is removed by the filter, and after that, the signal of a low distortion and a low noise is outputted from the output terminal. The isolation unit is connected between the amplifier and the filter, avoiding effects on the output impedance of the amplifier from the filter, so that a signal of a low distortion can be outputted.

Abstract: A predistortion circuit has an input terminal for inputting a predetermined signal; a nonlinear device directly or indirectly connected to the input terminal; a bias supply circuit for applying a voltage to the nonlinear device; specific-frequency suppressing means connected to one side or both sides of the nonlinear device directly without another intervening device and of suppressing all or part of such frequencies that are from a frequency corresponding to DC to a frequency corresponding to an occupied band width of an input signal inputted to the input terminal and/or suppressing at least one higher harmonic frequency of a carrier wave of the input signal; and an output terminal for outputting a signal.

Abstract: The present invention is directed to a data converter for converting an input signal to a signal to be inputted to an amplifier. The data converter includes: an amplitude detection section for detecting an amplitude level of the input signal; a region determination section for determining whether or not an input power to the amplifier is in a non-linear region of the amplifier based on the amplitude level of the input signal detected by the amplitude detection section; and a signal processing section for converting the input signal to a signal having a lower resolution than that of the input signal if the region determination section determines that the input power to the amplifier is in the non-linear region of the amplifier.

Abstract: A transmission circuit capable of transmitting a modulated wave signal using polar modulation in a broad band and with low power consumption is provided. The transmission circuit generates an amplitude signal and a phase signal based on data to be transmitted, and separates the amplitude signal into a low-frequency amplitude signal and a high-frequency amplitude signal. The transmission circuit amplitude-modulates the phase signal in a broad band using the high-frequency amplitude signal in a high-frequency voltage control section 104 and an amplitude modulation section 105 and amplitude-modulates the phase signal into low power consumption using the low-frequency amplitude signal in a low-frequency voltage control section 106 and amplitude modulation section 107.

Abstract: An amplifier circuit has: a delta-sigma modulator which delta-sigma modulates a signal; and an amplifier which is connected to an output of the delta-sigma modulator. In the amplifier circuit, an output voltage of the delta-sigma modulator is controlled in accordance with an output power of the amplifier. When the output power of the amplifier is reduced, the output voltage of the delta-sigma modulator is lowered.

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: The amplitude modulator comprises: an angle modulator for angle-modulating a phase signal to be inputted; a waveform shaping means in which, (1) when the magnitude of an amplitude signal to be inputted becomes smaller than a first prescribed value, a waveform of the amplitude signal is shaped so that the magnitude of the amplitude signal of the portion which becomes small becomes the first prescribed value; and/ or (2) the waveform shaping means in which, when the magnitude of the amplitude signal to be inputted becomes larger than the second prescribed value which is larger than the first prescribed value, the waveform of the amplitude signal is shaped so that the magnitude of the amplitude signal of the portion which becomes larger becomes the second prescribed value; and an amplitude modulator for amplitude modulating the signal of the output of the angle modulator by the signal of the output of the waveform shaping means.

Abstract: In the prior art, it has been difficult to provide a data generator and a data generating method which serve to implement an efficient transmitter, as well as a transmitter utilizing this data generator. The present invention provides a raw data generator that generates, from an inputted signal, an I signal and a Q signal which are orthogonal to each other and an amplitude component of a quadrature signal composed of the I and Q signals, a delta sigma modulator that delta-sigma-modulates the amplitude component, a first multiplier that outputs first data obtained by multiplexing normalized I data obtained by dividing the I signal by the amplitude component, by the delta-sigma-modulated signal, and a second multiplier that outputs second data obtained by multiplexing normalized Q data obtained by dividing the Q signal by the amplitude component, by the delta-sigma-modulated signal.