Abstract: A power amplifier circuit includes a first amplifier that, in a region where an input signal level is a first level or higher, amplifies a signal split from an input signal and outputs an amplified signal; a first converter connected to an output side of the first amplifier and converts an impedance on the output side of the first amplifier; and at least one or more second amplifiers that, in a region where the input signal level is a second level or higher, amplify a signal split from the input signal and output an amplified signal. Output sides of the second amplifiers are connected in series with an output side of the first converter. The first converter makes an absolute value of the impedance on the output side of the first amplifier larger than absolute values of impedances on the output sides of the second amplifiers.

Abstract: Systems, apparatuses, and method of measuring hydrophone impedance are provided herein. A sensor can convert an acoustic wave received via a liquid medium into an electric signal. A signal encoder can be coupled with the sensor to receive the electric signal. A test signal generator can be coupled in series with the sensor and the signal encoder and can generate a test signal. The test signal can measure an impedance of the sensor. A switch component can be coupled in series with the sensor, the signal encoder, and the test signal generator. The switch component can route the test signal to a first terminal of the sensor and through a second terminal of sensor during a first operational state. The switch component can route the test signal to the second terminal of the sensor and through the first terminal of sensor during a second operational state.

Abstract: A power amplifier includes: at least two first bridge type amplifying circuits and at least two second bridge type amplifying circuits; the negative pole of the first load of each first bridge type amplifying circuit is respectively coupled to the positive stage of the second load of each second bridge type amplifying circuits through a gating circuit. When both a first input signal input into one of the at least two first bridge type amplifying circuits and a second input signal input into one of the at least two second bridge type amplifying circuits are less than a preset threshold, the gating circuit is turned on, so that the one of the at least two first bridge type amplifying circuits and the one of the at least two second bridge type amplifying circuits can share load current by the gating circuit.

Abstract: A test and measurement probe system (100,104), including an input (106) to receive an input signal, the input signal including a low frequency (LF) and/or direct current (DC) component and an alternating current (AC) component, an extractor circuit (110), such as an AC coupling circuit or a LF and/or DC rejection circuit, configured to receive the input signal and to separate the AC component and the LF and/or DC component from the input signal, a first output (118) to output the alternating current component to the test and measurement instrument, and a second output to output the direct current component to the test and measurement instrument. In some embodiments, the LF and/or DC component is digitized prior to being output by the second output.

Abstract: A power amplifier circuit includes a first amplifier that amplifies an input signal and outputs an output signal; a second amplifier that, in accordance with a control signal, amplifies a signal corresponding to the input signal, generates a signal having an opposite phase to that of the output signal, and adds the signal to the output signal; and a control circuit that supplies the control signal to the second amplifier. The control circuit outputs the control signal so that during operation of the power amplifier circuit in a first power mode, a gain of the second amplifier is not less than zero and less than a predetermined level and during operation in a second power mode lower than the first power mode in output power level, a gain of the second amplifier is not less than the predetermined level and less than a gain of the first amplifier.

Abstract: There is provided a semiconductor integrated circuit including an input circuit. The input circuit includes a first amplifier and a second amplifier. The second amplifier is electrically connected to the first amplifier. The second amplifier includes a first transistor, a second transistor, a third transistor, a fourth transistor, and a time constant providing circuit. The first transistor has a gate electrically connected to a first node of the first amplifier. The second transistor has a gate electrically connected to a second node of the first amplifier. The third transistor is disposed adjacent to a drain of the first transistor. The fourth transistor is disposed adjacent to a drain of the second transistor. The time constant providing circuit is electrically connected between a gate of the third transistor and a drain of the third transistor, a gate of the fourth transistor.

Abstract: A method and an apparatus for envelope shaping of a multi-carrier signal in envelope tracking transmission are disclosed. According to an embodiment, a baseband version of an envelope portion belonging to each of multiple carriers in the multi-carrier signal is positioned such that a frequency spacing between adjacent positioned envelope portions is smaller than that between corresponding adjacent carriers. The positioned envelope portions are combined into a composite envelope. The composite envelope is shaped. The shaped composite envelope is split into baseband versions of shaped envelope portions belonging to the multiple carriers. The baseband versions of each shaped envelope portion is repositioned such that a frequency spacing between adjacent repositioned envelope portions is equal to that between corresponding adjacent carriers.

Abstract: A method of reducing memory effect of a power amplifier (PA), for a look-up table (LUT) based memory digital pre-distortion (DPD) circuit of an electronic device is disclosed. The method comprises generating a pre-distorted signal according to a LUT including parameters of an input signal amplitude and an input signal delay associated with a bandwidth of a signal inputted to the memory DPD circuit, and outputting the pre-distorted signal to the PA for improving the nonlinearity of the PA.

Abstract: A multi-voltage generation circuit and related envelope tracking (ET) amplifier apparatus is provided. In one aspect, a multi-voltage generation circuit is configured to generate a number of ET target voltages based on an analog voltage signal. In another aspect, a multi-amplifier ET circuit can be configured to include a number of amplifier circuits for amplifying concurrently a radio frequency (RF) signal based on a number of ET voltages. The multi-amplifier ET circuit also includes a number of driver circuits configured to generate the ET voltages base on a number of ET target voltages. In this regard, the multi-voltage generation circuit can be provided in the multi-amplifier ET circuit to generate the ET target voltages based on the analog voltage signal that corresponds to the RF signal. In examples discussed herein, the driver circuits are co-located with the amplifier circuits to help improve efficiency and maintain linearity in the amplifier circuits.

Abstract: A programmable gain amplifier includes an operational amplifier and a resistor network coupled to the output node of the operational amplifier. The resistor network includes a first plurality of resistors coupled in series between the output node and a first network node. A second plurality of resistors is coupled in series between the first network node and a second network node. A unit resistor is coupled in parallel with the second plurality of resistors between the first and second resistor network nodes and a third plurality of resistors is coupled in parallel between the second resistor network node and a reference voltage. Each resistor of the second and third pluralities of resistors comprises a unit resistor. The third plurality of resistors contains N resistors and the second plurality of resistors contains (N?1) resistors.

Abstract: A power amplification system comprises a pre-processor including a wavefront multiplexer, a set of power amplifiers, and a post-processor including a wavefront demultiplexer. The wavefront multiplexer receives concurrently N input signals, N being an integer greater than 2, performs a wavefront multiplexing transform on the N input signals by attaching N wavefronts to the N input signals respectively, and generates N first output signals. The N wavefronts are unique and mutually orthogonal. The wavefront multiplexing transform has an inverse. The N power amplifiers amplify the N first output signals and generate N amplified signals. The wavefront demultiplexer performs the inverse of the wavefront multiplexing transform on the N amplified signals and generates N second output signals, the N second output signals corresponding respectively to the N input signals. Each of the N second output signals is an amplified version of a corresponding one of the N input signals.

Abstract: Provided herein are apparatus and methods for low distortion composite amplifiers with high load current. In certain configurations, a composite amplifier can be a closed loop system which includes two or more amplifiers such that one or more amplifiers can provide an output current to a load while one or more amplifiers can control an output voltage to be proportional to an input voltage. The loop gain can be proportional to the product of the individual amplifier gains and to a noise gain network function. In this way the composite amplifier can maintain low distortion for heavier loads and for load currents which exceed the normal load current operation of a single amplifier.

Abstract: A Doherty power amplifier circuit is provided, which includes a power divider circuit, and a power amplifier circuit connected with the power divider circuit; this Doherty power amplifier circuit further includes a combination output circuit connected with the power amplifier circuit, wherein the combination output circuit is a rheostat filter coupler, or a rheostat filter, or a rheostat coupler. By adopting the circuit, the size of a power amplifier circuit can be reduced, the cost of the power amplifier circuit can be lowered, and the efficiency of a power amplifier can be improved.

Abstract: An amplifier comprises a main-amplifier circuit, an auxiliary-amplifier circuit and a signal-generating device. Output terminals of the main-amplifier circuit and of the auxiliary-amplifier circuit are connected according to the Doherty principle. The signal-generating device is configured to generate directly a main-amplifier signal as an input signal of the main-amplifier circuit and an auxiliary-amplifier signal as an input signal of the auxiliary-amplifier circuit.

Abstract: An object of the vehicle body vibration-damping control device according to the present invention is to achieve a targeted effect for damping the vehicle body vibration regardless of the responsiveness of an actuator for controlling the drive torque. The vehicle body vibration-damping control device has a body vibration estimating unit (205) for estimating a sprung mass behavior of a vehicle body based on input information during travel, and a torque command-value computing unit (206) for computing a correction torque value for correcting a drive torque command value applied to an engine (106) when the sprung mass behavior is controlled.

Abstract: The invention relates to a method and an apparatus for automatically tuning an impedance matrix, for instance the impedance matrix seen by the power amplifiers of a radio transmitter using a plurality of antennas simultaneously, and to a radio transmitter using this apparatus. An apparatus for automatically tuning an impedance matrix has 4 user ports and 4 target ports, and comprises: 4 sensing units; a signal processing unit, the signal processing unit estimating real quantities depending on the impedance matrix presented by the user ports, using the sensing unit output signals obtained for 4 different excitations applied successively to the user ports; a multiple-input-port and multiple-output-port tuning unit comprising adjustable impedance devices; and a tuning control unit delivering tuning control signals to the multiple-input-port and multiple-output-port tuning unit, the reactance of each of the adjustable impedance devices being mainly determined by one or more of the tuning control signals.

Abstract: Circuits and techniques to linearize the operation of an RF power amplifier are described. A linearizer circuit may include a non-amplification signal path which includes a delay line and an amplification signal path which includes at least one amplifier stage. In some embodiments, the amplification signal path may include an odd number of amplification stages. The linearizer may be used to precondition an input signal of an RF power amplifier in a manner that improves the overall linearity of operation.

Abstract: A satellite communications system includes a satellite configured to communicate with terminals, a station configured to communicate signals intended for the terminals to the satellite via a plurality of feeder links and a beamformer including an input multi-port hybrid matrix (MPHM) and a complementary output MPHM in a signal path with the plurality of feeder links. The output MPHM is positioned at the satellite and coupled to the input MPHM via the plurality of feeder links. For example, the input MPHM may be positioned at a ground-based satellite gateway. The input and output MPHMs may be configured to implement fully populated signal transformation matrices that collectively provide a substantially diagonal signal transformation matrix.

Abstract: In one embodiment, an amplifier system has a tap, a delay filter, a linearized amplifier, and a hybrid combiner. The tapped portion of an input signal is amplified by the amplifier, the untapped portion of the input signal is delayed by the delay filter, and the combiner combines the resulting amplified, tapped portion and the delayed, untapped portion to generate an amplified output signal. By re-combining the delayed, untapped portion of the input signal with the amplified, tapped portion, the power of the untapped portion is not lost, and the amplifier does not have to compensate for all of the distortion that would otherwise be associated with the total output power level. Such an amplifier system is applicable, for example, in upgrading an existing GSM cell site to support both GSM communications as well as UMTS communications without degrading GSM operations.

Abstract: A power-combined amplifier and method are provided. In one aspect, the power-combined amplifier and method overcome problems associated with decreased output power efficiency caused by phase mismatch between constituent amplifiers.

Abstract: A Lange coupler having a first plurality of lines on a first level and a second plurality of lines on a second level. At least one line on the first level is cross-coupled to a respective line on the second level via electromagnetic waves traveling through the first and second plurality of lines. The first and second plurality of lines may be made of metal, and the first level may be higher than the second level. A substrate may be provided into which the first and second plurality of lines are etched so as to define an on-chip Lange coupler.

Abstract: The even order harmonic distortion in a differential circuit is reduced or eliminated by treating the amplitude and phase mismatch sources that cause the distortion as impedance mismatches, and utilizing switched resistor circuitry that adjusts the load resistance to reduce the effects of the amplitude mismatch sources, and switched capacitor circuitry that adds shunt capacitance to reduce the effects of the phase mismatch sources.

Abstract: The invention relates to a receiver for a near-field chip-to-chip multichannel transmission system such as the capacitive or inductive links used for vertical signal transmission between the stacked chips of a system-in-package. A receiver for near-field chip-to-chip multichannel transmission providing 4 transmission channels for digital transmission between two monolithic integrated circuits comprises 4 coupling devices (211) (212) (213) (214), each of said coupling devices being a planar winding sensitive to magnetic field variations. A multiple-input-port and multiple-output-port amplifier (23) has 4 input ports, each of said input ports being connected to one and only one of said coupling devices (211) (212) (213) (214).

Abstract: A linearity power amplification device is provided. The device comprises a divider, a combiner, n?1 first signal paths, and a second signal path coupled between the divider and the combiner. The first signal path comprises a main invariable attenuator connected to the divider, a first power amplifier connected to the combiner, and a first attenuator and a first shifter coupled between the first power amplifier and the main invariable attenuator. The second signal path comprises a main amplification circuit, and an error calibration circuit.

Abstract: A system of detecting signal power may include a first interface port configured to receive a first signal. The system may also include a second interface port communicatively coupled to the first interface port and configured to receive a second signal. The second interface port may be communicatively coupled to the first interface port such that the first signal propagates from the first interface port to the second interface port and such that the second signal propagates from the second interface port to the first interface port. The system may further include a common signal detector communicatively coupled between the first interface port and the second interface port such that the common signal detector is configured to receive both the first and second signals and is configured to detect a first power level of the first signal and a second power level of the second signal.

Abstract: A generator of a high-power modulated signal, a method for calibrating the generator, and a magnetic resonance imaging system. The generator includes means for generating a sinewave signal phase-shifted by a first variable value relative to a phase reference and a sinewave signal phase-shifted by a given fixed value added to a second variable value relative to the phase reference, the second variable value opposite to the first variable value relative to the phase reference, the variable values representative of the modulation of the radiofrequency signal, the two sinewave signals being of constant amplitude, two amplifiers each amplifying one of the sinewave signals in a congested regime, and a fixed phase shifter with a value equal to the given value of the means to generate the two sinewave signals, the fixed phase shifter coupling the signals originating from the two amplifiers to deliver the modulated radiofrequency signal.

Abstract: Techniques for amplifying a plurality of input voltages to generate a corresponding plurality of output voltages. In an exemplary embodiment, each of the plurality of input voltages is referenced to a common voltage comprising the average of the plurality of input voltages, wherein for each of the input voltages, the common voltage is coupled to a common node via a corresponding switch.

Abstract: An apparatus is provided. There is an input terminal that is configured to receive an input signal from a optical receiver and an output terminal. First and second integrators are coupled between the input and output terminals. In the second integrator, there is a current source that is coupled to the input terminal, a first resistor that is coupled to the output terminal, and a second resistor. Also, there is an amplifier having a first input, a second input, and an output, where the first resistor is coupled to the first input of the amplifier and where the second input of the amplifier is configured to receive a reference voltage. A transistor is coupled between the current source the second resistor and is coupled to the output of the amplifier at its gate. A capacitor is also coupled between the first input of the amplifier and the second resistor.

Abstract: A high-voltage driver amplifier for piezo haptics comprises an input amplifier having a gain greater than one, a first amplifier of an amplifier pair coupled to an output of the input amplifier, a second amplifier of the amplifier pair coupled to the output of the input amplifier, a first impedance coupled between an output of the first amplifier of the amplifier pair and an input of the input amplifier, and a second impedance coupled between the output of the first amplifier of the amplifier pair coupled to an output of the second amplifier of the amplifier pair. A substantially capacitive load is coupled to the output of the second amplifier. The substantially capacitive load is a piezo-capacitance, wherein the piezo-capacitance is employed in haptics. The second impedance, a shunt impedance, allows for a feedback of output variations between the first amplifier and the second amplifier over the first impedance.

Abstract: A method for generating an amplified radio frequency (RF) signal is provided. In-phase (I) and quadrature (Q) signals are received and interleaved so as to generate a time-interleaved signal. Delayed time-interleaved signals are then generated from the time interleaved signal, and each of the delayed time-interleaved signals is amplified so as to generate a plurality of amplified signals. The amplified signals are then combined with a transformer, where the delayed time-interleaved signals are arranged to generate a filter response with the transformer.

Abstract: Included is a radio transmission system comprising a plurality of power amplifiers (PAs); a plurality of Volterra Engine (VE) linearizers corresponding to the PAs; a plurality of feedback loops corresponding to the PAs; at least one digital hybrid matrix (DHM) coupled to the VE linearizers; and an analog hybrid matrix (AHM) coupled to the PAs, wherein the feedback loops are connected to the AHM and the VE linearizers but not to the PAs to reduce the number of feedback loops. Also included is a radio system comprising a plurality of PAs; a Volterra DHM (VDHM) coupled to the PAs; a plurality of feedback loops corresponding to the PAs; and an AHM coupled to the PAs, wherein the feedback loops are connected to the AHM but not to the PAs to reduce the number of feedback loops.

Abstract: A multiport amplifier and a wireless device using the same are obtained in which isolation among output terminals is improved, whereby the quality of communication is improved. The multiport amplifier includes an input hybrid, an output hybrid, a plurality of amplifiers and a plurality of gain and phase control circuits that are inserted between the input hybrid and the output hybrid, a plurality of output coupling circuits that are inserted between the output hybrid and a plurality of output terminals so that they receive output extraction signals corresponding to a plurality of output signals, and a feedback circuit including a frequency selection circuit that is inserted between the plurality of output coupling circuits and the plurality of gain and phase control circuits.

Abstract: A wireless communication system that includes a robust transmitter array. The robust transmitter array includes an antenna array system with at least one column, at least one antenna element, and at least one polarization, a plurality of transmitter devices to transmit analog voice/data signals through the antenna array system, and a signal processor. The signal processor modifies two or more input signals in the event of a transmitter device failure such that substantially similar amounts of each of the two or more input signals are output from the transmitter system to the antenna array system, and wherein substantially less transmitted signal power is lost than in the case wherein the signal processor does not modify the two or more input signals in the event of a transmitter failure.

Abstract: An amplifier comprises a main amplification stage and an auxiliary amplification stage. An input of the main amplification stage and an input of the auxiliary amplification stage are coupled to a common node, and an output of the main amplification stage is coupled to an output node. During activation, before power is supplied to the main amplification stage, the output node is coupled to a reference voltage (VREF). A quiescent voltage is then established at the common node by coupling power to the auxiliary amplification stage. Only then is power coupled to the main amplification stage and the reference voltage (VREF) de-coupled from the output node.

Abstract: A system for multi-distributed amplification of a communication signal including at least one plurality N of input pathways connected to an input Butler matrix which delivers as output N distributed signals, a plurality N of tube amplifiers which receive as input said distributed signals and produce as output N amplified and phase-shifted signals each of a complex gain Gi and an output Butler matrix which receives as input said amplified signals and produces as output N output signals, wherein the phase error and amplitude error are self-compensated in the presence of traffic.

Abstract: An operational amplifier can include a plurality of amplifiers connected to form a plurality of amplification paths extending from an input terminal to an output terminal of the operational amplifier. An amplifier in one of the amplification paths can include an intrinsic amplification-transistor capacitance connected between a first amplifier input and a first amplifier output, and a cross-coupling capacitor connected between the first amplifier input and a second amplifier output. A plurality of the amplification paths can include series-connected amplifiers connected in parallel with the cross-coupled amplifier. The cross-coupling capacitor can have a capacitance value selected as a function of the intrinsic capacitance and a gain experienced between the amplifier inputs and outputs. The operational amplifier can include an AC coupling capacitor connected in series with the cross-coupled amplifier. The operational amplifier can be arranged in feedback configuration.

Abstract: A new type of amplifier, herein designated a resource pooling amplifier, involves extended usage of one or more inductors that is implemented by sharing. The sharing is either by switching the inductor or inductors among more than one load terminal at the same time (e.g., a bridged configuration or two different loads terminals with different polarity requirements) or by using the inductor or inductors for more than one purpose at different times. The inductor or inductors may be time shared such as by allocating different phases of a clock. The inductor or inductors may also be shared by monitoring load requirements and using the inductor or inductors only when needed (leaving other inductor cycles for other loads). In addition, inductor sharing may be implemented during different application requirements such as if two or more loads are not needed at the same time in a system. These types of sharing may be combined.

Abstract: An amplifier arrangement with an amplifier arrangement input and an amplifier arrangement output is disclosed. The amplifier arrangement comprises a first transistor and a first ballast resistance, wherein the first ballast resistance connects a first transistor base of the first transistor to a common base terminal at least one second transistor and at least one second ballast resistance, wherein the at least one second ballast resistance connects a second transistor base of the at least second transistor to the common base terminal; and a feedback device comprising a feedback input terminal for sensing at least a base voltage of the first transistor and further comprising a feedback output terminal that is connected to the common base terminal.

Abstract: A transmitter that uses a digital pre-distortion (DPD) circuit to mitigate the effects of nonlinearity of a multistage or multi-branch power amplifier. The DPD circuit relies on two or more feedback signals received from an RF-output circuit of the transmitter to generate individually pre-distorted signals for the individual stages/branches of the power amplifier. The use of these individually pre-distorted signals advantageously enables the transmitter to achieve a more efficient suppression of inter-modulation-distortion products than that typically achieved with a comparable prior-art transmitter.

Abstract: There is disclosed an amplifier arrangement comprising a plurality of amplifiers each arranged to amplify one of a plurality of different input signals, the arrangement comprising an envelope tracking modulator for generating a common power supply voltage for the power amplifiers, and further comprising an envelope selector adapted to receive a plurality of signals representing the envelopes of the plurality of input signals, and adapted to generate an output envelope signal representing the one of the plurality of envelopes having the highest level at a particular time instant as the input signal for the envelope tracking modulator.

Abstract: A multiport amplifier modulates a reference quadrature phase shift keying (QPSK) signal using an input RF signal to an input hybrid network, generates a plurality of binary phase shift keying (BPSK) signals by demodulating RF signals that are amplified by a plurality of power amplifiers, detects an amplitude error and a phase error of two corresponding amplified RF signals by comparing a QPSK signal that is generated by coupling two RF signals having a phase difference of 90° among the plurality of BPSK signals with a reference QPSK signal, and compensates the detected amplitude error and phase error.

Abstract: A power amplifier using N-way Doherty structure with adaptive bias supply power tracking for extending the efficiency region over the high peak-to-average power ratio of the multiplexing modulated signals such as wideband code division multiple access and orthogonal frequency division multiplexing is disclosed. In an embodiment, the present invention uses a dual-feed distributed structure to an N-way Doherty amplifier to improve the isolation between at least one main amplifier and at least one peaking amplifier and, and also to improve both gain and efficiency performance at high output back-off power. Hybrid couplers can be used at either or both of the input and output. In at least some implementations, circuit space is also conserved due to the integration of amplification, power splitting and combining.

Abstract: Included is a radio transmission system comprising a plurality of power amplifiers (PAs); a plurality of Volterra Engine (VE) linearizers corresponding to the PAs; a plurality of feedback loops corresponding to the PAs; at least one digital hybrid matrix (DHM) coupled to the VE linearizers; and an analog hybrid matrix (AHM) coupled to the PAs, wherein the feedback loops are connected to the AHM and the VE linearizers but not to the PAs to reduce the number of feedback loops. Also included is a radio system comprising a plurality of PAs; a Volterra DHM (VDHM) coupled to the PAs; a plurality of feedback loops corresponding to the PAs; and an AHM coupled to the PAs, wherein the feedback loops are connected to the AHM but not to the PAs to reduce the number of feedback loops.

Abstract: A power amplifier (10) comprises: an A/D converter (11) for converting, to a time discrete signal, an envelope signal included in a high-frequency modulated signal and including only an amplitude modulated component of the high-frequency modulated signal; a switching amplifier (12) for amplifying the output signal of the A/D converter (11); a low-pass filter (13) for removing high frequency noise from the output signal of the switching amplifier (12); a plurality of high-frequency power amplifiers (15-1 to 15-n) for receiving the output signal of the low-pass filter (13) as a power supply and for amplifying a carrier signal included in the high-frequency modulated signal; and a power controller (14) for adjusting the average power of the output signal of the power amplifier (10) by controlling the total gains of the plurality of high-frequency power amplifiers (15-1 to 15-n).

Abstract: A signal distributor sequentially outputs N input signals respectively corresponding to N rows of a matrix of which each has N element signals in which a predetermined matrix is obtained by dividing the matrix by a predetermined value. A coupler adds the amplified N element signals for each the input signal. A solver computes feedback signals Y* for the individual amplifiers by using an addition result Y of the outputs for each the input signal and the inverse matrix L?1 of the predetermined matrix.

Abstract: A post phase-inverter master volume regulator for use in combination with a tube-type musical amplifier having a phase-inverter tube. The signals at both sides of the phase-inverter tube's DC voltage plate are extracted from the amplifier for processing by the master volume regulator. In one embodiment, such signals are extracted by inserting a male/female tube base between the amplifier's phase-inverter tube and its socket. The two voltage plate signals are then transmitted through a multiconductor umbilical to an exterior enclosure. Each signal is connected to ground through its respective user adjustable rheostat, permitting the user to simultaneously change the inverter-tube's two voltage signals (and vary the amplifier's volume). The regulator may also include circuitry adapted to provide a bass-boost, and/or a high frequency cutoff. Sometimes, first and second volume controls may be provided to permit a user to quickly change between two volume settings.

Abstract: A multiport amplifier and a wireless device using the same are obtained in which isolation among output terminals is improved, whereby the quality of communication is improved. The multiport amplifier includes an input hybrid, an output hybrid, a plurality of amplifiers and a plurality of gain and phase control circuits that are inserted between the input hybrid and the output hybrid, a plurality of output coupling circuits that are inserted between the output hybrid and a plurality of output terminals so that they receive output extraction signals corresponding to a plurality of output signals, and a feedback circuit including a frequency selection circuit that is inserted between the plurality of output coupling circuits and the plurality of gain and phase control circuits.

Abstract: A radio frequency amplifier amplifies a modulation signal or its phase modulation signal and outputs the resultant signal. A linear amplifying section adds an output voltage to a power supply voltage supplied to the radio frequency amplifier and negatively feeds back the power supply voltage supplied to the radio frequency amplifier such that the power supply voltage matches the amplitude modulation component of the modulation signal with a predetermined ratio. A control signal generation section detects a direction in which an output current of the linear amplifying section flows and generates a pulse modulation signal according to the direction of the current. A switching amplifying section controls connection and disconnection of a DC current based on the pulse modulation signal as a control signal so as to perform switching amplification for an output signal of the linear amplifying section and supply the resultant signal as the power supply voltage to the radio frequency amplifier.

Abstract: An error amplifier may be part of a voltage regulator and may include a single feedback input configured to receive a feedback signal. A single error output may be configured to provide an error output signal indicative of error in the feedback signal. A comparison circuit may be configured to provide an error signal to the single error output which is indicative of a difference between the feedback signal and whichever one of a set of reference signals is closest to the feedback signal. One or more of these reference signals may each be derived from an offset from a ground reference. One or more of the other reference signals may each be derived from an offset from a non-ground reference, such as a source of power for the error amplifier. The error amplifier may be on a single integrated circuit along with an associated driver circuit.

Abstract: The invention relates to an amplifier capable of delivering a plurality of output signals, these output signals being controlled by a plurality of input signals. A multiple-input and multiple-output amplifier of the invention comprises a common input terminal, 4 signal input terminals, 4 signal output terminals, a common terminal amplifier, 4 active sub-circuits and a feedback network. Each active sub-circuit has a sub-circuit input terminal connected to one of the signal input terminals, a sub-circuit output terminal connected to one of the signal output terminals and a sub-circuit common terminal. The feedback network has four C terminals and one R terminal. Each of said C terminals of the feedback network is coupled to the sub-circuit common terminal of one of said active sub-circuits. The output terminal of the common terminal amplifier is coupled to said R terminal of the feedback network.