A method for generating a control signal for an acousto-optical element includes generating a raw signal using at least one correction term by an IQ modulation from a target I component and a target Q component, and amplifying the raw signal to become the control signal. The target I component and/or the target Q component are corrected using the at least one correction term. The at least one correction term is obtained from an analysis of the control signal.

A radio frequency device with mechanisms for adjustment of the impedances and frequencies of its antennas comprises a first circuit board, a radio frequency module and a second circuit board. The radio frequency module is disposed on the first circuit board that is disposed on the second circuit board. The radio frequency module comprises an antenna unit, a first frequency tuning element and a radio frequency circuitry. The antenna unit is disposed within a clearance area of the first circuit board, and connected to the radio frequency circuitry via a feeding circuit. The second circuit board comprises a second frequency tuning element that is electrically connected to the antenna unit via a ground circuit and the first frequency tuning element on the first circuit board. Thus, the resonance frequency of the antenna unit can be adjusted according to the first and the second frequency tuning element.

The method of phase modulating a carrier wave involves creating a set of signals s.sub.h(t) constituted by a carrier wave of frequency f.sub.C and of phase (t)=h.sub.0(t) that is modulated in time t in such a manner that s.sub.h(t)=cos(2f.sub.Ct+h.sub.0(t)), where h is an integer and where .sub.0(t)=2 arctan((tt.sub.0)/w.sub.0). The modulation corresponds to a single phase pulse centered on a time t.sub.0 of characteristic duration w.sub.0 that is positive, and incrementing the phase of the signal s.sub.h(t) by the quantity h2, in such a manner as to generate a single sideband frequency spectrum directly. The carrier wave may be of electromagnetic type or of acoustic type. The method applies in particular to transporting binary information by single sideband phase coding, to generating single sideband orthogonal signals, to detecting single sideband phase coded multiple-level digital signals, to transmitting single sideband phase coded binary signals in-phase and out-of-phase, and to single sideband combined amplitude-and-phase modulation.

The method of phase modulating a carrier wave involves creating a set of signals s.sub.h(t) constituted by a carrier wave of frequency f.sub.C and of phase (t)=h.sub.0(t) that is modulated in time t in such a manner that s.sub.h(t)=cos(2f.sub.Ct+h.sub.0(t)), where h is an integer and where .sub.0(t)=2 arctan((tt.sub.0)/w.sub.0). The modulation corresponds to a single phase pulse centered on a time t.sub.0 of characteristic duration w.sub.0 that is positive, and incrementing the phase of the signal s.sub.h(t) by the quantity h2, in such a manner as to generate a single sideband frequency spectrum directly. The carrier wave may be of electromagnetic type or of acoustic type. The method applies in particular to transporting binary information by single sideband phase coding, to generating single sideband orthogonal signals, to detecting single sideband phase coded multiple-level digital signals, to transmitting single sideband phase coded binary signals in-phase and out-of-phase, and to single sideband combined amplitude-and-phase modulation.

An audio system includes a processor including an input configured to: receive a baseband audio signal and modulate the baseband audio signal to create a modulated audio signal comprising audio signal frequency components in a first frequency range; clip the modulated audio signal to create a clipped, modulated audio signal the clipped modulated audio signal comprising the audio signal frequency components in the first range and further comprising distortion frequency components outside the first frequency range. The system can further be configured to filter the clipped, modulated audio signal to remove frequency components outside the first frequency to remove distortion components outside that frequency range.

An audio system includes a processor including an input configured to: receive a baseband audio signal and modulate the baseband audio signal to create a modulated audio signal comprising audio signal frequency components in a first frequency range; clip the modulated audio signal to create a clipped, modulated audio signal the clipped modulated audio signal comprising the audio signal frequency components in the first range and further comprising distortion frequency components outside the first frequency range. The system can further be configured to filter the clipped, modulated audio signal to remove frequency components outside the first frequency to remove distortion components outside that frequency range.

A method and a transmission device of a mobile communication system are disclosed. The method includes determining a modulation method for data transmission, determining the level of a quadrature amplitude modulation (QAM) according to the determined modulation method, determining the amplitude of a carrier wave and the phase of the carrier wave on the basis of the determined QAM level and the data to be transmitted, and, when the determined modulation method is a first modulation method, determining a sequence length, selecting a sequence form among sequences having the determined length according to the data to be transmitted, and generating a symbol modulating the data to be transmitted, on the basis of the selected sequence, the determined amplitude of the carrier wave, and the determined phase of the carrier wave.

A system that incorporates teachings of the subject disclosure may include, for example, determining a first voltage standing wave ratio (VSWR), selecting a VSWR circle from among a group of VSWR circles based on the first VSWR, identifying a group of sets of tuning settings for variable reactance elements of a matching network of the communication device where the identifying of the group of sets of tuning settings is based on each set of tuning settings of the group of sets of tuning settings being associated with the VSWR circle, and selecting a set of tuning settings from among the group of sets of tuning settings responsive to a second VSWR determined for the set of tuning settings satisfying a VSWR threshold. Other embodiments are disclosed.

A digital amplitude modulation device includes power amplifiers, a compositor, a filter, a measurement unit, a protection unit, and a controller. The power amplifiers are arranged in parallel and amplify an input signal in accordance with ON control and stop output in accordance with OFF control. The filter suppresses an unnecessary component to generate an AM signal. The measurement unit measures a measurement value between the filter and a signal output terminal and output the AM signal generated by the filter. The protection unit includes a calculator and a first processing unit. The calculator is formed from an analog circuit and calculates an evaluation value based on the measurement value. The first processing unit is formed from an analog circuit and generates a first control signal by referring to the evaluation value. Upon receiving the first control signal, the controller OFF-controls the power amplifiers.

Provided is a non-contact communication apparatus which uses a conventional IC chip without any change, while eliminating the need to transmit power to the IC chip and allowing an increase in communication range. A non-contact communication apparatus connectable to an IC chip includes an antenna section, a first detection section that retrieves a first detection signal from a signal received by the antenna section, an amplitude modulating section that amplitude-modulates a clock signal using the first detection signal retrieved by the first detection section and that inputs the amplitude-modulated signal to the IC chip, a second detection section that retrieves a second detection signal from an output signal from the IC chip, a load modulating section that load-modulates a carrier retrieved from the antenna section using the second detection signal retrieved by the second detection section and that inputs the load-modulated carrier to the antenna section, and a power supply section.