Abstract: A method for compensating a transceiver for impairments includes transmitting a plurality of partial bandwidth training signals using a transmitter. A plurality of response signals of a receiver having a bandwidth and exhibiting receiver impairments is captured. Each response signal is associated with one of the partial bandwidth training signals. Each of the partial bandwidth training signals is associated with a portion of the receiver bandwidth. A plurality of partial compensation filters is generated based on the plurality of response signals. Each partial compensation filter is associated with one of the response signals. The partial compensation filters are combined to configure a receiver compensation filter operable to compensate for the receiver impairments.

Abstract: A method processes defects in a radio frequency transmission subsystem due to elements therein. The defects may include mismatch between two channels in phase quadrature in the transmission subsystem and a transposition signal leaking from a first frequency transposition stage of the transmission subsystem. The method may include calibration processing including estimating compensation parameters representative of the defects. The estimating may include delivering, into the transmission subsystem upstream of the elements creating the defects, a reference signal having a reference frequency, obtaining, downstream of the first transposition stage, of a resultant reference signal, and obtaining, from the resultant reference signal, of an approximate value for each compensation parameter. The method also may include compensating for the defects by injecting the approximate values into the transmission subsystem.

Abstract: A high frequency power amplifier maintains an excellent linearity regardless of a fluctuation of a load impedance and is downsized. The high frequency power amplifier detects an AC voltage amplitude at an output terminal of a final amplification stage transistor, and suppresses an input signal amplitude of a power amplifier when the voltage amplitude exceeds a predetermined threshold value.

Abstract: A system and method of automatically tuning a reading device that remotely monitors RFID tags or transponders. The reading device utilizes the phase signal of an antenna signal wherein the harmonic of the antenna signal is filtered through a signal coupling transformer and utilizes the antenna current reading to determine the optimal capacitance setting for the reader by adjusting capacitors and storing the relative phase signal and level of current in a processor. In one embodiment, the method comprises supplying power to the reading device, monitoring the power supply, storing data related to the monitored power supply, emitting a signal from an antenna, filtering the harmonic of such signal, outputting the phase signal to a processor and adjusting capacitors based on the phase signal and monitored current.

Abstract: A harmonic suppression device includes a multilayer printed circuit board (PCB). The multilayer PCB includes a first layer, a second layer, and a third layer. The third layer is connected to the ground. The first layer is configured with a power amplifier, an input microstrip, a voltage divider microstrip, and an output microstrip. The power amplifier is operable to amplify radio frequency (RF) signals input using the input microstrip and to output the amplified RF signals using the output microstrip. The second layer is configured with a first microstrip and a second microstrip. One end of each of the first and second microstrips is connected to an alternative one of the first layer and the third layer by vias, and the other ends of the first and second microstrips are unattached so as to suppress harmonics on the power amplifier.

Abstract: Various embodiments of systems and methods for generating local oscillator (LO) signals for a harmonic rejection mixer are provided. One embodiment is a system for generating local oscillator (LO) signals for a harmonic rejection mixer. One such system comprises a local oscillator, a divide-by-N frequency divider, a divide-by-three frequency divider, and a harmonic rejection mixer. The local oscillator is configured to provide a reference frequency signal. The divide-by-N frequency divider is configured to divide the reference frequency signal by a value N and provide an output signal. The divide-by-three frequency divider is configured to receive the output signal of the divide-by-N frequency divider and divide the output signal into three phase-offset signals. The harmonic rejection mixer is configured to receive the three phase-offset signals and eliminate third frequency harmonics.

Abstract: A local oscillator circuit for a signal transmitter or receiver, the circuit comprising: an input for receiving a master oscillating signal from a master oscillator; and signal processing circuitry configured to be clocked by the master oscillating signal to generate a local oscillator signal, the signal processing circuitry being such that the local oscillator signal has substantially no harmonic content at any integer multiple of the frequency of the master oscillator signal, which oscillates at (2n+1)/2 times the frequency of the generated local oscillator signal, with n being a positive integer.

Abstract: Aspects of a method and system for a programmable interference suppression module may include receiving a communication signal comprising one or more desired signal, and one or more undesired signals. The communication signal may be utilized to generate estimated channel state information. The estimated channel state information may be formatted for use in interference suppression. A reduced interference signal may be generated from a delayed version of said communications signal and the estimated channel state information, wherein the one or more undesired signals may be attenuated. The reduced interference signal may be formatted for post-processing. The desired signals may comprise WCDMA and/or HSDPA signals, and the undesired signals may be inter-cell and/or intra-cell interference. Further processing may comprise HSDPA processing and/or RAKE finger processing. The communication signal may be a Universal Mobile Telecommunication System (UMTS) compliant signal.

Abstract: A mobile wireless communications device includes a portable housing having a metallic front housing forming a peripheral sidewall as a metallic ring. A circuit board is carried by the portable housing and forms a chassis ground plane. A wireless communications circuit is carried by a circuit board. An antenna circuit is carried by a circuit board and connected to the wireless communications circuit. A frequency selective grounding circuit is positioned at a selected grounding location at the chassis ground plane and metallic front housing and forms a harmonic trap that responds to a specific range of frequencies.

Abstract: Implementations and examples of power amplifier devices, systems and techniques for amplifying RF signals, including power amplifier systems based on Composite Right and Left Handed (CRLH) metamaterial (MTM) structures.

Abstract: A radio-frequency switch circuit of the invention includes: n-stage through FETs (field effect transistors) connected in series between the antenna terminal and each of the radio-frequency terminals, where n is a natural number; a radio-frequency leakage prevention resistor connected to a gate of the through FETs; a control signal line commonly connected to the gates of the n-stage through FETs connected to the same radio-frequency terminal; and a resistor connected to each of at least two of the control signal lines and connected to the radio-frequency leakage prevention resistor in series The two control signal lines are capacitively coupled between the resistor and the through FETs.

Abstract: Various embodiments of systems and methods for generating local oscillator (LO) signals for a harmonic rejection mixer are provided. One embodiment is a system for generating local oscillator (LO) signals for a harmonic rejection mixer. One such system comprises a local oscillator, a divide-by-N frequency divider, a divide-by-three frequency divider, and a harmonic rejection mixer. The local oscillator is configured to provide a reference frequency signal. The divide-by-N frequency divider is configured to divide the reference frequency signal by a value N and provide an output signal. The divide-by-three frequency divider is configured to receive the output signal of the divide-by-N frequency divider and divide the output signal into three phase-offset signals. The harmonic rejection mixer is configured to receive the three phase-offset signals and eliminate third frequency harmonics.

Abstract: The present invention relates to an apparatus and method for feedforward-type phase noise elimination in a portable terminal, which detect and eliminate phase-reversed phase noise by subtracting a GSM transmission signal, passed through the power amplifier of a GSM transmission device, from a GSM transmission signal, extracted from an upstream stage of the power amplifier, so that phase noise signals attributable to high-power transmission signals.

Abstract: Embodiments for at least one method and apparatus of a wireless transceiver are disclosed. For one embodiment, the wireless transceiver includes a transmit chain, wherein the transmit chain includes a power amplifier. The wireless transceiver additionally includes a receiver chain that is tunable to receive wireless signals over at least one of multiple channels, wherein the multiple channels are predefined. Further, the wireless transceiver includes a voltage converter. The voltage converter provides a supply voltage to the power amplifier, and operates at a single switching frequency, wherein the single switching frequency and all harmonics of the single switching frequency fall outside of the multiple channels.

Abstract: A radio communication device capable of lightening the influence of a frequency selective fading in the wide-band transmission of a single carrier thereby to prevent deterioration of error rate characteristics. In this device, an FFT unit (13) subjects a modulated signal inputted from a modulation unit (12) to a Fourier transformation. A pilot insertion unit (14) inserts a pilot symbol into a plurality of individual frequency components (1-N) of the modulated signal. Weight multiplication units (15-1, 15-2) multiply the individual frequency components (1-N) and the pilot symbols inserted into the individual frequency components (1-N), by weight coefficients (W11-W1N, W21-W2N) set at a weight coefficient setting unit (54). IFFT units (16-1, 16-2) subject the frequency components (1-N) to an inverse Fourier transformation, thereby to convert the frequency components (1-N) into time domains.

Abstract: The function of comparing power of a signal obtained by multiplying an input signal by an EVM target value and power of a peak suppression signal, and automatically adjusting a peak factor threshold value Vt in such a manner that the values of both power become equal to each other, is added to the peak factor reduction device. The peak factor reduction device is also added with the function of comparing instantaneous amplitude values of a signal Sout after a peak factor reduction and the peak factor threshold value Vt, and automatically calculating a peak detection width N so as to suppress the residual of each peak.

Abstract: A mobile wireless communications device includes a circuit board carried by a housing. A microprocessor, RF transceiver and circuitry are carried by the circuit board and operative with each other. Clock buffer circuitry is carried by the circuit board and connected to the RF transceiver and circuitry and microprocessor for isolating a clock signal from the noise of the microprocessor and allowing greater isolation for the RF transceiver from RF circuitry.

Abstract: A multi-carrier transmission device improves peak suppression efficiency in a multi-carrier signal. The multi-carrier transmission device (100) has a peak suppression unit (140) for dividing a multi-carrier signal into two parts: a first multi-carrier signal and a second multi-carrier signal. A peak signal detection unit (142) detects a power value at a predetermined interval concerning the first multi-carrier signal. When the detected power value is equal to or above a predetermined level, a peak extraction unit (144) extracts a signal component equal to or above the predetermined level from the first multi-carrier signal. A band limit filter unit (146) passes only a predetermined band from the extracted signal component. An adder (154) subtracts the signal component after the band limit from the second multi-carrier signal.

Abstract: An integrated transceiver for wireless applications has both a frequency determining means and a power amplifier. A transmission filter suppresses unwanted spurious outputs in an integrated circuit before a power amplifier stage amplifies and transmits the desired signal. A differential to single ended converter is able to be implemented to further enhance efficiency.

Abstract: A system and method are disclosed for controlling transmitter output levels in a wireless communications device. The system comprises: a transmitter configured to accept an adjusted transmit bias control value and to supply a transmitter output level in response to the adjusted transmit bias control value; and a gain control circuit configured to supply the adjusted transmit bias control value in response to a transmitter output measurement and to a reference.

Abstract: A semiconductor integrated circuit includes a first input terminal configured to input a baseband signal, a second input terminal configured to input a local oscillation signal, an output terminal configured to output a modulating signal, a first amplifier circuit configured to receive the baseband signal through the first input terminal and to output a first amplified signal of the baseband signal, a 2-multiplying circuit configured to receive the local oscillation signal through the second input terminal and to output a 2-multiplied signal of the local oscillation signal, an adder configured to add the 2-multiplied signal and the first amplified signal and to output an addition signal, a second amplifier circuit configured to receive the addition signal and to output a second amplified signal of the addition signal, and a mixer configured to multiply the second amplified signal and the local oscillation signal and to output the modulating signal to the output terminal.

Abstract: A radio communication device in which the output transmission signal of a high-frequency power amplifying part is sent out to an antenna via a circulator, a high-frequency signal reflected from the antenna is transferred via the circulator to a rectifying part to obtain a direct current power, and the direct current power is supplied to a power amplifying part or another constituent part in the radio communication device as an aid to the power supply from a power supply unit.

Abstract: Methods and apparatus for dynamically compensating for signal variations in communications transmitters employing switch-mode PAs. An exemplary method includes first identifying a predetermined signal characteristic in an input signal applied to an input of a switch-mode PA. A modulated signal produced at the output of the switch-mode PA containing the identified signal characteristic is then sampled at approximately the same time the identified signal characteristic appears at the output of the switch-mode PA, to generate a digital sample representing an actual value of the identified signal characteristic. An error signal representing the extent to which the actual value deviates from an expected value is then generated. Finally, the DC level and/or gain of the input signal to the switch-mode PA is modified to reduce the error. By reducing the error in this manner, signal variations that adversely affect the accuracy of the switch-mode PA output signal are dynamically compensated for.

Abstract: A transceiver for radio-frequency communication comprises a waveguide, a transmitting port, a receiving port and a receiver load termination. The waveguide receives and transmits radio-frequency signals. The transmitting port is connected to the waveguide and transmits the radio-frequency signals to the waveguide. The receiving port is connected to the waveguide and receives the radio-frequency signals from the waveguide. The receiver load termination is connected to the waveguide and removes the vertical polarization components of the receiving radio-frequency signals. The receiver load termination includes a filtering unit to reduce the energy of the transmitting radio-frequency signals entering the receiver load termination.

Abstract: This invention provides a wireless transmitter circuit for mobile communication apparatus and this circuit can be configured with fewer components and is suitable for downsizing. A single PLL synthesizer serves as both RF frequency band PLL and IF frequency band PLL among three oscillators for TX, RX and IF frequency bands, which have been required in conventional mobile communication apparatus. The number of necessary oscillators occupying a large area within a chip is reduced and the number of components is decreased. Specifically, circuitry is arranged to generate local oscillation signals for RF and IF frequency bands by frequency dividing the output of a VCO of the RF frequency band PLL.

Abstract: Embodiments of circuits, devices, and methods for a power detection arrangement are disclosed. The power detection arrangement may have a coupler coupled with, and in between, a switch and an output to couple a signal to a detector. The power detection arrangement may include a harmonic suppressor coupled with, and in between, the coupler and the detector to reduce an amount of harmonic signals transmitted back to the coupler. Other embodiments may be described and claimed.

Abstract: A technique to mitigate in-band spurs introduced into a signal due to various board/SiP layout issues at a receiver is disclosed. The spurs can be approximated as sinusoids at different known frequencies with unknown amplitudes and phases. The technique is applicable to both single and multiple spur cancellation.

Abstract: A distortion compensating apparatus includes following units. An information measuring unit measures a distortion component and an electric power component based on a radiation signal. A compensation coefficient calculating unit calculates a compensation coefficient based on the distortion component and the electric power component. A signal transmitting unit outputs a signal corrected by the compensation coefficient as a transmission signal. A signal converting unit converts the transmission signal into a high frequency signal. An amplitude separating unit amplifies the high frequency signal and separates a portion thereof as a signal to be fed back. A feeding-back unit processes the portion and outputs the result as a feedback signal to the information measuring unit.

Abstract: Systems and methods may be provided for transmitter calibration. The systems and methods may include providing one or more radio frequency (RF) test signals at an output of a transmitter, wherein the one or more RF test signals are based upon IQ baseband test signals, and applying an envelope detector to the one or more test signals to obtain one or more characteristic signals from the one or more RF test signals, where the one or more characteristic signals includes one or more first harmonic components and one or more second harmonic components associated with the one or more RF test signals. The systems and methods may further include analyzing the one or more second harmonic components to determine one or more IQ mismatch compensation parameters, and analyzing the one or more first harmonic components to determine one or more carrier leakage or DC offset compensation parameters.

Abstract: The radio telecommunication terminal (2) comprises a data burst scheduler able to schedule the continuous transmission of consecutive data bursts which generate noise of similar energy on the radio-frequency channel as long as a specific radio-frequency channel is used to receive a radio signal, the respective energy of the noise generated by the transmission of two consecutive first and second data burst being similar only if the noise energy gradient between the end of the transmission of the first data burst and the beginning of the transmission of the second data burst is situated between predetermined upper and lower limits.

Abstract: A combined matching and harmonic rejection circuit with increased harmonic rejection provided by a split resonance for one or more of the capacitive or inductive elements of the circuit. At a fundamental frequency, the circuit comprises an inductive series arm with capacitive shunt arms. The capacitance of a shunt arm may be provided by two or more parallel paths, each having a capacitor and an inductor in series so that, in addition to providing the effective capacitance necessary for impedance matching at the fundamental frequency, two separate harmonics represented by the series resonances of the parallel paths are rejected. In this manner, an extra null in the circuit's stop-band may be achieved using the same number of shunt elements necessary to achieve impedance matching at the fundamental frequency.

Abstract: There are included an LPF (3) and an HPF (4) that are connected in parallel to the output of a pre-emphasis circuit (2). There is also included a gain adjusting circuit (6) that performs a gain adjustment of low-pass filter with respect to the frequency band to be passed through the HPF (4). The low frequency components of the frequency band of baseband signals outputted from the pre-emphasis circuit (2) pass through the LPF (3), while the high frequency components pass through the HPF (4). As to the outputs from the HPF (4), the gain of especially the higher part of the frequency band components to be passed through the HPF (4) is suppressed by the gain adjusting circuit (6), whereby the amplitudes of the baseband signals can be limited only for the high frequency range without using a limiter and further the peak values of the baseband signals can be inhibited from exceeding the maximum frequency deviation.

Abstract: Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

Abstract: An amplifier circuit includes a first power amplifier that can produce a first amplified signal in response to a first input signal in a first frequency band, and a second power amplifier that can produce a second amplified signal in response to a second input signal in a second frequency band. A center frequency of the second frequency band is higher than the a center frequency of frequency band A control circuit can turn on or turn off the first power amplifier and configured to turn on or turn off the second power amplifier. A shunting circuit is coupled to an output of the second power amplifier. The shunting circuit can attenuate harmonic signals from the first frequency band under the control of the control circuit.

Abstract: An example of a radio frequency (RF) receiver system for communication may include a receive channel frequency converter configured to provide a second receive calibration signal during a receive calibration mode based on a first receive calibration signal and a receive reference signal. The system may include a receive pre-distortion module coupled to the receive channel frequency converter. The receive pre-distortion module may be configured to provide a fourth receive calibration signal during the receive calibration mode based on a third receive calibration signal and one or more receive calibration adjustment signals. The one or more receive calibration adjustment signals may comprise an offset parameter associated with DC offset and an imbalance parameter associated with at least one of gain and phase imbalances.

Abstract: A semiconductor device interconnecting unit configured to input/output a high-frequency signal having a millimeter wave band to/from a semiconductor device is provided. The semiconductor or device interconnecting unit includes a part of a band pass filter configured to pass therethrough the high-frequency signal having a millimeter wave band by using an LC resonance circuit, and a remainder of the band pass filter, wherein the part and the remainder are separated from each other. The part is provided inside the semiconductor device, and the remainder is provided outside the semiconductor device. The part and the remainder include capacitors having variable capacitors added thereto, respectively. A pass band for the high-frequency signal having a millimeter wave band is changed by changing capacitance values of the variable capacitors.

Abstract: A limiter for minimizing an amount of phase change caused by input amplitude variation includes a variable gain amplifier configured to receive a signal having an amplitude component and a phase component and having a gain controlled by a compensation capacitance and a variable resistance, in which the compensation capacitance minimizes an effect of parasitic capacitance and the variable resistance adjusts a gain in the variable gain amplifier such that the amplitude component at an output of the variable gain amplifier remains substantially constant.

Abstract: The present invention relates to an antenna matching device that varies a frequency bandwidth according to mobile communication services, and to a transceiver having the same. To this end, an exemplary embodiment of the present invention provides a transceiver that varies a frequency band and a bandwidth according to required services in a mobile communication system, the transceiver including an antenna matching controller that generates a prescribed switch control signal according to a service requested by a user, an antenna variable matching unit that variably forms a matching circuit according to the switch control signal to be transmitted from the antenna matching controller and varies the frequency band and the bandwidth, an analog processing unit that processes a signal to be transmitted/received through the antenna variable matching unit, and a wideband antenna that transmits/receives a radio frequency according to the frequency band and the bandwidth set by the antenna variable matching unit.

Abstract: An amplifier includes an RF power amplifier and a predistortion circuit coupled to the power amplifier. The predistortion circuit affects an input path of an RF input signal to the power amplifier. The predistortion circuit is operable for detecting a level of an input signal and generating a delay in the input path based on the input signal level. This enables predistortion correction of a new distortion term AM/DM, in addition to the well known AM/AM and AM/PM terms. The new AM/DM term represents the distortion that is caused by the delay modulation of the input signal as a function of the envelope power variation within the input signal.

Abstract: Methods and systems to calibrating a transmitter for I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting DC offsets. The adjusting optionally includes an iterative refinement process.

Abstract: A system for an omni digital package for reducing interference may include a passive combiner and a transmit signal canceller. The passive combiner may be configured to combine at least two input frequencies to produce a combined signal. The transmit signal canceller may be configured to determine an interference frequency based on a combination of the at least two input frequencies. The transmit signal canceller may include a tap weight determiner configured to determine a weighting coefficient associated with the interference frequency, and a cancellation function configured to perform a cancellation operation to at least partially cancel the interference frequency from the combined signal based on the weighting coefficient.

Abstract: An apparatus and method for attenuating a leakage signal of a transmitter in a communication system is provided. The apparatus includes a local oscillator, a mixer, and a leakage signal attenuator. The local oscillator outputs a reference frequency signal. The mixer adds the reference frequency signal to an IF signal to convert the IF signal into an RF signal, and outputs the RF signal, a leakage signal and an image signal. The leakage signal attenuator extracts a partial signal from the reference frequency signal output from the local oscillator, adjusts the amplitude of the extracted signal, shifts the phase of the extracted signal, and combines the resulting signal and the output signal of the mixer, to remove the leakage signal.

Abstract: A Multi-mode-multi-band direct conversion receiver with complex I and Q channel interference mitigation processing for cancellation of intermodulation products (IMPs) are described. In one embodiment, a method comprising over sampling of the entire receiver passband to acquire the IMP source signals that can generate IMPs within the signal of interest (SOI), generate a coherent complex I-Q channel estimates of the interference, generating estimates of 2nd and 3rd order IMP products, sampling of the transmitter feed thru signal and blocking signals and computing the cross modulation products estimate, using the cross modulation cancellation to cancel of the effects of the on chip transmitter feed thru to support building a single transceiver chip with full duplex operation, and creation of an estimate of the DC offset in the receiver in a closed loop fashion to cancel the DC offset in the I and Q channels independently and simultaneously, and adjusting the rate of update to match system parameters.

Abstract: A communication system (10) has an audio receiver path (12), and a digital transceiver path (14), wherein both paths (12, 14) are integrated on a single integrated circuit. The audio receiver path (12) has a concealment device (16), and the communication system (10) also has at least one functional block (18) connected to and shared by the both paths (12, 14). The communication system (10) has a digital controller (20) connected to both paths (12, 14), the at least one functional block (18), and the concealment device (16). The digital controller (20) is operable to schedule the operation of the digital transceiver path (14), and to inform the concealment device (16) of start and end points of the activity of the digital transceiver path (14). The concealment device (16) is operable to mask interruptions in the audio stream from the audio receiver path (12) caused during periods of activity of the digital transceiver path (14).

Abstract: An integrated automatic IIP2 calibration architecture for wireless transceivers is disclosed. The architecture enables a wireless transceiver to generate a test radio frequency (RF) signal having a second order tone with minimal additional circuitry. In particular, the test RF signal is generated using a combination of native transceiver circuits and test adaptor circuits. Native transceiver circuits are those circuits implemented on the transceiver chip for executing native transceiver functions during normal operation, which can be used for generating the test (RF) signal. Test adaptor circuits are added to the transceiver chip, more specifically to the native circuits, for enabling the native circuits to generate the test RF signal in a self-test mode of operation. Circuits for implementing a particular IIP2 minimizing scheme can be included on the transceiver chip for automatic IIP2 calibration during the self-test mode of operation.

Abstract: Disclosed is a mixer comprising: a switching circuit, having a first pair of differential signal nodes and a second pair of differential signal nodes, for switching according to a local oscillation signal; an amplifying stage circuit, for receiving an input signal and amplifying the input signal; a load circuit, for serving as the loading of the mixer and generating an output signal of the mixer; a common-mode feedback circuit, for receiving the output signal and generating a feedback signal according to the output signal; a first current source, for receiving the feedback signal and generating a first current according to the feedback signal; and a second current source, for receiving the feedback signal and generating a second current according to the feedback signal.

Abstract: In a multimode communication apparatus that uses a plurality of wireless communication modes, interference between communications under different wireless communication modes is suppressed, a good transmission/reception state in each of the wireless communication modes is ensured. A multimode communication apparatus (100) includes transmitter sections (33), (43) and receiver sections (32), (42) and a plurality of communication units (70), (80) each being compatible with the wireless communication modes independently of one another. The communication unit (70) includes a variable channel band elimination filter (34) for suppressing, among transmission signals from its own transmitter section (33), a band corresponding to a frequency band of a reception channel that is being received by the receiver section (42) of the other communication unit (80).

Abstract: In a representative embodiment, an electronic transmitter comprises a signal source configured to provide an input signal comprising a plurality of frequency components; and a plurality of transducers each configured to receive the input signal and each configured to resonate substantially at one frequency of a subset of the plurality of frequency components. An electronic receiver, an acoustic transmitter and an acoustic receiver are also described.

Abstract: A high-frequency circuit for use in a dual-band wireless communications apparatus selectively using first and second frequency bands, comprising a diplexer connected to the output of a power amplifier for sending either one of transmission signals in the first and second frequency bands to an antenna, a coupler having a primary line connected to a common end of the diplexer and a secondary line, a detector comprising a detection diode for detecting a transmission power of a high-frequency signal sent from the secondary line of the coupler, and a harmonics-suppressing circuit disposed between the secondary line of the coupler and the detection diode.

Abstract: Disclosed is a direct conversion type transmitter or transceiver circuit suitable for a mobile communication device which corresponds to broad signal output level variable width to be required by W-CDMA, which does not necessitate any high-performance low noise VCO and RF filter, capable of reducing a number of components and the cost. In the input portion of an orthogonal modulator composed of a divider, mixers, and a common load, there are provided variable attenuators. If an input signal level of the orthogonal modulator within the transmitter circuit lowers, this variable attenuator circuit is operated so as to lower the bias of the orthogonal modulator to reduce the amount of occurrence of carrier leak, and to prevent the signal during low output level and carrier leak ratio from being deteriorated.