Abstract: A dynamic power amplifier advantageously employed in a wireless terminal for transferring and receiving signals from a base terminal includes an input amplifier adapted to receive an input signal having a given power signal level corresponding to the distance of said wireless terminal to the terminal and adapted to provide an amplifier output signal having a given power output signal level. The dynamic amplifier further includes a power sensor configured to receive the power output signal and to generate a power indication signal corresponding to the power output signal, and a converter adapted to receive the power indication signal in order to generate a biasing signal corresponding to the power indication signal. The biasing signal is applied to the input amplifier so that the operating bias point of the power amplifier varies as a function of the power indication signal.

Abstract: A bipolar transistor current mirror circuit has the bases of its input and output transistors connected together, but decouples the input transistor's collector from its base so that the mirror input voltage is no longer tied to the input transistor's base-emitter voltage. Instead, a separate base current source supplies sufficient base current to the mirror's input transistor to keep it in saturation, while a parasitic transistor that results from a junction isolated fabrication process drains off excess current from the base current source to keep it in balance with the mirror transistor base currents. The resulting input voltage is a function of the input transistor's saturated collector-emitter voltage, which is substantially lower than the base-emitter voltage and provides more voltage head room.

Abstract: A load monitor module for measuring voltage and current supplied from an amplifier to a load is provided within an amplifier and includes a device for calculating an impedance of the load and an amount of power delivered to the load from the amplifier. The load monitor module includes a voltage measuring device and a current measuring device for accurately measuring the voltage and current of a generated test signal or an audio signal input the amplifier signal path without substantially altering the signal. The monitor module also includes a controller for controlling the performance of the amplifier and load according to the calculated load impedance and power input to the load from the amplifier.

Abstract: A high power bipolar transistor includes bipolar transistors disposed on a substrate; a signal line including a pad for inputting a driving signal and a signal transmission line continuous with the pad commonly connecting base electrodes of the bipolar transistors; and a bypass line having a first end connected to the signal transmission line proximate to the pad and a second end connected to the signal transmission line remote from the pad. Approximately equal powers are supplied to the transistors connected to any position on the base feed line so that the operation of the respective transistors is uniform, improving output power and efficiency.

Abstract: An operational amplifier and a digital signal transfer circuit in which an output voltage does not decrease instantly even if an abrupt change of input signal due to noise causes a high-to-low transition to be superposed on an input signal. The operational amplifier includes a differential pair of transistors with a first transistor having a collector that is grounded and a second transistor having an emitter connected to the emitter of the first transistor; a current mirror circuit with a third transistor having a collector connected to an output node of the differential pair of transistors and a fourth transistor having a base connected to a base of the third transistor; a fifth transistor having a collector connected to an output terminal and a base connected to an output node of the current mirror circuit; and a capacitive element connected between the output node of the current mirror circuit and the output terminal.

Abstract: An amplifier amplifies a signal derived from the output of a voltage-controlled oscillator. The frequency control voltage applied to the voltage-controlled oscillator is also applied, after suitable level conversion, to the amplifier as a gain control signal, to correct frequency-dependent power deviation of the amplifier.

Abstract: An OTA capable of low-voltage operation at a voltage as low as approximately 1 V while restraining the circuit scale increase and keeping approximately the same input voltage range as that of the conventional one. This OTA has a differential pair of first and second bipolar or MOS transistors driven by a first constant current source, and a squarer driven by a second constant current source. The differential pair is applied with an input voltage and produces an output current of the OTA. The squarer is applied with the input voltage and produces differentially first and second output currents having a square-law characteristic. The first constant current source supplies a first constant current equal to a second constant current supplied by the second constant current source. The second output current of the squarer is supplied to the first constant current source.

Abstract: An RF power amplifier including a splitter, two branch circuits, and a combiner. The splitter has an input line receiving an RF signal, a first output line carrying a first output signal derived from the RF signal, and a second output line carrying a second output signal derived from the RF signal. A first branch circuit receives the first output signal and generates therefrom a first derived signal. A second branch circuit receives the second output signal and generates therefrom a second derived signal therefrom. The first branch circuit includes a first power amplifier and a phase shifting element. The second branch circuit includes a second power amplifier. The combiner, which has a first input receiving the first derived signal and a second input receiving the second derived signal, combines the first and second derived signals to produce a power output signal therefrom.

Abstract: A current sourcing output stage for a high voltage operational amplifier receives a low voltage input signal (V.sub.IN) and provides a high current output signal corresponding to the low voltage input signal at an output terminal (8). A first PNP transistor (Q1) is coupled between a voltage supply (V.sub.CC) and a plurality of cascaded PNP transistors (Q2, Q3, Q8-Q11) coupled to the output terminal (8). The base of the first PNP transistor (Q1) is coupled to receive the input signal (V.sub.IN) and the bases of the cascaded PNP transistors are coupled to receive different bias voltages A control circuit (Q5-Q7, R1-R5) is coupled to the voltage supply (V.sub.

Abstract: A signal amplifier includes four amplifier stages which can be arranged in two different configuration modes, a first configuration mode in which a series arrangement of two loads is arranged between output terminals of a first and a third one of the amplifier stages, a reference potential being applied to a node between the loads, a first signal to be amplified being applied to an input of the first amplifier stage, and a second signal to be amplified being applied to an input of the third amplifier stage, and a second configuration mode in which a first one of the loads is arranged between the output terminal of the first amplifier stage and an output terminal of a second amplifier stage, and a second one of the loads is arranged between the output terminal of the third amplifier stage and an output terminal of a fourth amplifier stage, and the first signal to be amplified being applied to an input of the first amplifier stage and an input of the second amplifier stage and the second signal to be amplified

Abstract: A limiting transimpedance amplifier includes an amplifier stage including a feedback resistor, a limiting diode coupled across the feedback resistor, and a stabilization diode coupled to the amplifier stage to compensate for feedback instability introduced by the limiting diode. The amplifier stage includes an input transistor and an output transistor, where the feedback resistor couples an output of the output transistor to an input of an input transistor. A stabilization voltage generator is coupled to the stabilization diode to provide a stabilization voltage that causes the desired compensation.

Abstract: In this hybrid amplifier circuit the vacuum tube is direct coupled or DC coupled to the output of a solid state amplifier in a cathode follower configuration. An automatically operative bypass component, such as a Zener diode, LED, transistor junction or relay, diverts the signal output of the solid state amplifier around the vacuum tube stage when bias conditions or other vacuum tube operating conditions signify that the vacuum tube is still warming up or for some reason inoperative. Thus the hybrid circuit produces amplification at full volume and at low distortion even while the vacuum tube is warming up. The vacuum tube provides a desirable warming coloration to the sound that may be user adjusted by controlling the level of closed loop feedback within the circuit. Lower total harmonic distortion is achieved in a pentode vacuum tube device by direct coupling the screen and control grids. Lower voltage use of power pentodes wired in nonconventional "triode mode" is achieved.

Abstract: In a method and by an apparatus for correction of error signals and for forming of an arbitrary transfer function being independent of the quality of a payload (loudspeaker; H1) included in a signal amplification system, a control system (9) is used for supplying of the input signal to a basic amplifier (1) driving the payload. Said control unit includes a further amplifier (9) having an inverted input being supplied with a feedback signal from the output of the basic amplifier. In such a case the further amplifier involves only an inverted input, said input signal is supplied through one (4) of the resistors (3, 4) included in the feedback loop.

Abstract: The present invention provides an operational amplifier circuit which comprises an input circuit for outputting a difference between first and second input voltages, an amplifier circuit for amplifying the difference, a drive circuit for driving a latter stage in response to output from the amplifier circuit and an output circuit which constitutes the latter stage, wherein the amplifying circuit has a serial circuit composed of a first constant current source and a first transistor and a serial circuit composed of a second constant current source and a second transistor, the emitter of the first transistor is connected to the base of the second transistor, and the difference is applied to the base of the first transistor; the drive circuit has a serial circuit composed of third and fourth transistors whose collectors and emitters are interconnected and a third constant current source, the base and collector of the fourth transistor are interconnected, and the base of the third transistor is connected to the e

Abstract: Operating on the principle of vector summation, a predistortion linearizer includes a signal divider on one side of a substrate plate that divides a microwave signal into a linear portion and a nonlinear portion. Signal energy on both the nonlinear and linear portions is coupled into two respective slotline transmission lines on the substrate by uniplanar Magic T hybrids. As the signals are transmitted along the slotlines, their relative amplitudes and phases are adjusted to introduce a distortion inverse to that expected in a subsequent amplification. The linear portion and nonlinear portion pass through another pair of baluns. The signals are then combined by an in-phase summation on the same side of the plate as the input signal divider.

Abstract: An amplifier circuit with improved turn-on transient operation includes a differential amplifier and a selectively variable reference generator for controlling the amplifier output during circuit turn-on. The amplifier is biased by a single power supply and its differential inputs are driven by a reference voltage from the reference generator and a single-ended input signal. Following circuit turn-on, the selectively variable reference voltage, generated by charging the bypass capacitor with a constant current source, charges in a linear manner from ground potential toward its final value of, typically, half of the power supply voltage. This allows improved turn-on transient operation to be realized, e.g. reduced "pops" and "clicks" upon circuit turn-on, while giving the user increased flexibility in selecting the sizes of the reference voltage bypass capacitor and the input signal coupling capacitor.

Abstract: A self-biased, fully differential, complementary receiver apparatus and method is presented. The receiver accepts differential inputs that can vary over the full rail-to-rail common mode voltage range. It produces double-ended complementary outputs swinging rail-to-rail useful in signal level conversion and comparator applications. The receiver includes a dual, fully complementary and mirror-symmetrical arrangement of a differential input stage, a biasing stage and an output stage. A self biasing voltage is generated with a balanced voltage divider coupled between the outputs of the biasing stages. This frees both biasing outputs for use as analogous but complementary receiver outputs while providing the receiver with all the advantages of self bias. For small signal differential inputs, the input and biasing stages operate in their linear region useful for amplifier applications.

Abstract: A high-speed transmission line receiver includes a basic differential amplifier stage along with a gain enhancement stage, which is generally similar to the differential amplifier stage. One of the current mirror transistors in the gain enhancement stage is connected to one of the current mirror transistors in the basic amplifier stage in such a way that the magnitude of the differential current at the output of the basic amplifier stage is increased, thereby increasing the gain of the receiver without increasing its output capacitance or the time constant of the output signal. Preferably, the transistors in the gain enhancement stage are larger than the transistors in the basic amplifier stage. Increasing the gain of the line receiver reduces the distortion which may occur as a result of the failure of the line receiver to reach a clamping voltage as the common mode of the differential input signal is increased.

Abstract: An automatic gain control circuit is provided, which has minimum variations in the output signal level even with the presence of variations in component parts thereof and the temperature dependency of component parts thereof and can therefore dispense with the use of an additional amplifier circuit for adjusting the output level. An input signal-attenuating circuit attenuates the level of an input signal to a voltage amplifier circuit. An output level-detecting circuit detects the voltage level of an output signal from the voltage amplifier circuit to thereby carry out feedback control by controlling the attenuating characteristic of the input signal-attenuating circuit in response to the detected voltage of the output signal such that the voltage level of the output signal from the voltage amplifier circuit is maintained at a constant level.

Abstract: First and second amplifiers are coupled together to provide complementary output signals at respective output terminals in response to application of operating potentials to first and second supply terminals of each amplifier and application of an input signal to at least the first amplifier. A switching circuit, responsive to a first level of a tri-state control signal supplied thereto, applies the operating potentials individually to the first and second supply terminals of each amplifier and concurrently couples the input signal to the input of the first amplifier and, responsive to a second level of the tri-state control signal, isolates all of the amplifier supply terminals and decouples the input signal. Transient disturbances are minimized by AC coupling the input signal and applying a common mode signal from a common mode source to the AC coupling, to a reference input of each amplifier and to the output terminal of each amplifier.