Abstract: Techniques for improving linearity of amplifiers are described. In an exemplary design, an amplifier (e.g., a power amplifier) may include a plurality of transistors coupled in a stack and at least one diode. The plurality of transistors may receive and amplify an input signal and provide an output signal. The at least one diode may be operatively coupled to at least one transistor in the stack. Each diode may provide a variable bias voltage to an associated transistor in the stack. Each diode may have a lower voltage drop across the diode at high input power and may provide a higher bias voltage to the associated transistor at high input power. The at least one transistor may have higher gain at high input power due to the higher bias voltage from the at least one diode. The higher gain may improve the linearity of the amplifier.

Abstract: An adjustable resonator filter comprised of cavity resonators. There is a movable conductive tuning element in the filter for adjusting each electromagnetic coupling, which element is located outside the resonator cavities. When the coupling between two resonators is the case, the movement of the tuning element changes the coupling between the signal ground and a fixed coupling element which extends from a resonator cavity to the next cavity, whereupon the strength of the coupling between the resonators changes. When the coupling between a resonator and the input/output line of the filter is the case, by means of the tuning element it is implemented a section with a low impedance inside a range with a relatively high impedance on the transmission path. This section moves together with the tuning element, in which case the strength of the coupling between the resonator and the line changes.

Abstract: In a representative embodiment, a multiple mode power amplifier that is operable in a first power mode and a second power mode. The multiple mode power amplifier comprises a first amplifying unit; a second amplifying unit; a first impedance matching network connected to an output port of the first amplifying unit; a second impedance matching network connected to an output port of the second amplifying unit and to the first impedance matching network; and a third impedance matching network connected to the output ports of the first and the second amplifying units. The third impedance matching network reduces a phase difference between signals amplified by the first and the second amplifying units in the first mode.

Abstract: A tuner includes a plurality of paths, and at least one of the paths includes a front-end filter circuit, an amplifier, and a trace filter. The trace filter includes a varactor and an inductor, which are coupled to an output end of the amplifier. Further, the amplifier and the varactor of the tuner are packed in a complementary metal-oxide semiconductor (CMOS) chip.

Abstract: A method and apparatus are provided for using an automatic BW adjustment circuit to automatically adjust the bandwidth of an electronic amplifier based on the amplitude of a signal that is output from a variable gain amplifier or of one or more variable gain stages that follow the amplifier. By automatically adjusting the bandwidth of the electronic amplifier based on the amplitude of the signal, bandwidth enhancement can be provided while also preventing, or at least reducing, peaking of the frequency response of the electronic amplifier.

Abstract: Disclosed is a high-frequency signal processing device capable of reducing transmission power variation and harmonic distortion. For example, the high-frequency signal processing device includes a pre-driver circuit, which operates within a saturation region, and a final stage driver circuit, which operates within a linear region and performs a linear amplification operation by using an inductor having a high Q-value. The pre-driver circuit suppresses the amplitude level variation of a signal directly modulated, for instance, by a voltage-controlled oscillator circuit. Harmonic distortion components (2HD and 3HD), which may be generated by the pre-driver circuit, are reduced, for instance, by the inductor of the final stage driver circuit.

Abstract: This disclosure is directed to devices and integrated circuits for instrumentation amplifiers. In one example, an instrumentation amplifier device uses two non-inverted outputs of a first multiple-output transconductance amplifier, and a non-inverted output and an inverted output of a second multiple-output transconductance amplifier. Both multiple-output transconductance amplifiers have a non-inverted output connected to an inverting input, and a non-inverting input connected to a respective input voltage terminal. A first resistor is connected between the inverting inputs of both multiple-output transconductance amplifiers. The outputs of both multiple-output transconductance amplifiers are connected together, connected through a second resistor to ground, and connected to an output voltage terminal. In other examples, two pairs of outputs from triple-output transconductance amplifiers are connected to provide two voltage output terminals, and may also be connected to buffers or a differential amplifier.

Abstract: Embodiments provide a gm-ratioed amplifier. The gm-ratioed amplifier comprises a first input voltage terminal and a second input voltage terminal, a first output voltage terminal and a second output voltage terminal, and an amplifying unit. The amplifying unit may be coupled between the input voltage terminals and the output voltage terminals and may be adapted to supply an output voltage to the output terminals in dependence on an input voltage supplied to the input terminals. The amplifying unit may comprise a gm-load, which comprises a first load branch comprising a first field effect transistor, and a second load branch comprising a second field effect transistor. A first source/drain terminal and a gate terminal of the first field effect transistor may be coupled to the first output voltage terminal, and a first source/drain terminal and a gate terminal of the second field effect transistor may be coupled to the second output voltage terminal.

Abstract: Systems and methods for a filtering wave energy using a rectangular-to-circular waveguide transition are discussed herein. An exemplary system comprises a rectangular-to-circular waveguide transition and a filter card. The rectangular-to-circular waveguide transition may include a front section and a back section opposite the front section, the rectangular-to-circular waveguide transition defining a circular hole extending from the front section of the rectangular-to-circular waveguide transition through the back section, the rectangular-to-circular waveguide transition further having a first arcuate region on the face of the transition, the first arcuate region defining a first cavity extending from the circular hole through the first arcuate region, the rectangular-to-circular waveguide transition also having a second arcuate region defining a second cavity opposite the first cavity, the second cavity extending from the circular hole through the second arcuate region.

Abstract: A signal amplifying circuit includes: an input stage circuit, arranged to receive an input signal; a first inductive device coupled between the input stage circuit and a first reference voltage; an output stage circuit arranged to generate an output signal according to the input signal; and a second inductive device coupled between the output stage circuit and a second reference voltage, wherein at least a part of a winding of the first inductive element is cross-coupled to at least a part of a winding of the second inductive element.

Abstract: The present invention concerns an apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate an output signal in response to a differential input signal, a first power supply and a ground. The output signal may have a rail-to-rail voltage with a magnitude between the first power supply and the ground. The first circuit may also be configured to source an intermediate differential signal in response to the differential input signal, the first power supply and ground. The second circuit may be configured to sink the differential intermediate signal in response to the differential input signal, the first power supply, ground and a second power supply. The second circuit may flatten the transconductance of the first circuit relative to a common mode voltage of the differential input signal.

Abstract: A signal branching filter according to the invention is a signal branching filter connected to a network having at least four terminals. The signal branching filter includes a first line one end of which is connected to a first terminal of the network, a second line one end of which is connected to a second terminal of the network, a third line one end of which is connected to a third terminal of network, and a fourth line one end of which is connected to a fourth terminal of the network. The other end of the first line and the other end of the second line are connected to each other at a first node, and the other end of the third line and the other end of the fourth line are connected to each other at a second node. When a signal is received from the first node, a phase difference between a phase of a signal appearing on a second node side of the third line and a phase of a signal appearing on a second node side of the fourth line is almost 180°±360°*n is an integer equal to or larger than 0).

Abstract: An amplifier includes a first stage, a second stage coupled to the first stage, and a summation circuit. The first stage is configured to receive an analog input signal, convert the analog input signal to a digital signal, and output an intermediate analog output signal in response to the digital signal. The second stage is configured to output a second analog intermediate output signal based on a scaled pulse width modulation quantization error of the first stage. The summation circuit is configured to combine the first and second analog intermediate output signals to generate an amplified output signal.

Abstract: A power amplifier system includes a transistor stack and an upper portion. The upper portion includes an LC tank. The LC tank is configured to generate selected harmonics to mitigate voltage stress and facilitate amplifier efficiency. The transistor stack includes serial connected input transistors and upper transistors. The input transistors are configured to receive an input signal and the upper transistors are configured to provide an amplifier output signal. The LC tank is configured to provide the selected harmonics to at least gates of the upper transistors.

Abstract: A circuit includes a first amplifier and a second amplifier, wherein first amplifier is configured to receive an input current at a first input of the first amplifier, and an output of the first op-mp is configured to drive a first input of the second amplifier. The circuit further includes a pull-up current source selectively coupled to the first input of the second amplifier, and a pull-down current source selectively coupled to the first input of the second amplifier. If the absolute value of the input current is larger than a predefined threshold current: i) the pull-up current source is configured to drive current into the first input of the second amplifier for a first polarity of the input current, and ii) the pull-down current source is configured to sink current from the first input of the second amplifier for a second polarity of the input current.

Abstract: A signal transmission device includes substrates and resonance sections resonating at the predetermined resonance frequency. At least one of the substrates is formed with two or more resonators in the second direction, and the remaining one or two or more of the substrates are each formed with one or more resonators in the second direction, and at least one of the resonance sections is configured by a plurality of resonators opposing one another in the first direction between the substrates, the opposing resonators form a coupled resonator resonating as a whole at the predetermined resonance frequency through electromagnetic coupling in a hybrid resonance mode, and in a state that the substrates are separated away from one another to fail to establish electromagnetic coupling thereamong, the resonators forming the coupled resonator resonate at any other resonance frequency different from the predetermined resonance frequency on the substrate basis.

Abstract: A differential amplifying circuit includes: two metal oxide semiconductor transistors to form a differential pair and receive a differential signal; a plurality of capacitance elements coupled in series between drains of the two metal oxide semiconductor transistors; and an inductance circuit coupled between at least one connection node of the plurality of capacitance elements and a bias power terminal.

Abstract: An electromagnetic coupler includes a first plane, a plurality of conductive patterns formed on the first plane and spaced apart from each other, a second plane parallel to the first plane, a ground pattern formed on the second plane and connected to ground, a first linear conductor formed to have a length shorter than ¼ a wavelength equivalent to a frequency used, the first linear conductor being connected at one end to one conductive pattern of the plural conductive patterns, and fed between an other end of the first linear conductor and the ground pattern, and a plurality of second linear conductors formed to have a length shorter than ¼ the wavelength equivalent to the frequency used, one or more of the second linear conductors being formed for each of the plural conductive patterns, to connect each of the plural conductive patterns and the ground pattern.

Abstract: A microwave device having a narrow gap between two parallel surfaces of conducting material by using a texture or multilayer structure on one of the surfaces. The fields are mainly present inside the gap, and not in the texture or layer structure itself, so the losses are small. The microwave device further comprises one or more conducting elements, such as a metal ridge or a groove in one of the two surfaces, or a metal strip located in a multilayer structure between the two surfaces. The waves propagate along the conducting elements. At least one of the surfaces is provided with means to prohibit the waves from propagating in other directions between them than along the ridge, groove or strip. At very high frequency the gap waveguides and gap lines may be realized inside an IC package or inside the chip itself.

Abstract: An optical module for an atomic oscillator using a quantum interference effect includes a light source adapted to emit light including a fundamental wave having a predetermined wavelength, and sideband waves of the fundamental wave, a wavelength selection section receiving the light from the light source, and adapted to transmit the sideband waves out of the light input, a gas cell encapsulating an alkali metal gas, and irradiated with light transmitted through the wavelength selection section, and a light detection section adapted to detect an intensity of light transmitted through the gas cell, and the wavelength selection section includes a fiber Bragg grating, and a voltage application section adapted to apply a voltage to the fiber Bragg grating.