Abstract: To improve voice sound quality using a vacuum tube amplifier. A reactive load that has impedance characteristics, in which impedance characteristics in a first frequency band includes a first impedance characteristic pattern selected from a plurality of first impedance characteristic pattern candidates on the basis of a type of a vacuum tube amplifier, and impedance characteristics in a second frequency band includes a second impedance characteristic pattern selected from a plurality of second impedance characteristic patterns on the basis of the type of the vacuum tube amplifier, outputs a signal that responds to a sound signal output from the vacuum tube amplifier in accordance with the impedance characteristics and performs correction on an output signal of the reactive load.
Abstract: To be easy for a user to judge difference of sound quality of an audio signal that is output in a balanced mode and sound quality of the audio signal that is output in an active control ground mode. A DAP 1 has a balanced mode and an ACG mode. In the balanced mode, an analog audio data is amplified by an amplifier 8, a negative-phase data of the analog audio data is amplified by an amplifier 9, and the amplified analog audio data and the amplified negative-phase data are mixed so as to be output. In the ACG mode, the analog audio data is amplified by the amplifier 8 and ground is maintained by the amplifier 9. The CPU 2 decreases volume of the analog audio data that is output in the balanced mode compared with volume of the analog audio data that is output in the ACG mode.
Abstract: An oscillator circuit comprises a push-push oscillator and a differential output, comprising a first and a second output circuit. The push-push oscillator has a first and a second branch. Each of the first and second branch comprises an own voltage divider branch of a common bridge circuit. Each of the first and second voltage divider branches comprises an own pair of micro-strip lines connected in series. Each of the first and second voltage divider branches has an own tap. Both taps are connected to each other by at least one of a first capacity and a micro-strip line. The differential output comprises a first and a second output terminal. The first output terminal is connected via the first output circuit to a first node. The second output terminal is connected via the second output circuit to a second node. Each of the first and second nodes of the push-push oscillator is a common node of both of the first and the second branches.
Abstract: An audio device and an audio input/output method are described, which is coupled to an audio port, and includes a capacitor, a load, an output amplifying module, and an input amplifying module. The capacitor and the load are coupled to the audio port. The output amplifying module is operated at a first working voltage, for outputting a first audio signal to the audio port. A direct current (DC) level of the first audio signal is substantially zero volts. The input amplifying module is operated at a second working voltage, in order to receive a second audio signal from the audio port. When the audio port is in an output state, the output amplifying module is enabled and the input amplifying module is disabled, and when the audio port is in an input state, the input amplifying module is enabled and the output amplifying module is disabled.
Abstract: The present disclosure relates to coupled circuits and methods of coupling circuits having a power supply wherein a plurality of transistors are inductively coupled directly to the power supply for providing a single DC supply voltage directly to each of the plurality of transistors, and wherein a plurality of transformers have primary and secondary windings, the primary and secondary windings providing, at least in part, inductive loads for inductively coupling the plurality of transistors to the power supply, the plurality of transformers also providing an AC signal path for coupling neighboring ones of the plurality of transistors together.
August 2, 2006
Date of Patent:
September 20, 2011
The Regents of the University of California
Mau-Chung Frank Chang, Daquan Huang, Tim Richard LaRocca
Abstract: A power amplifier amplifying and compositing differential signals and capable of suppressing harmonics is provided. The power amplifier includes first amplifiers amplifying a first input signal and a second input signal, which are differential signals, a first coil receiving the first input signal and the second input signal amplified by the first amplifiers, a second coil magnetically coupled with the first coil and outputting a composite signal of the amplified first input signal and second input signal, a third coil magnetically coupled with the second coil, and a first capacitor coupled between both ends of the third coil, wherein one end of the first capacitor is coupled to a ground node.
Abstract: A system and method to optimize the efficiency of an amplifier device is provided by the including a non-linear amplifier in a mobile radio device. A phase displaced signal in relation to the input signal is respectively produced in the amplifier device with a non-linear power amplifier and in a plurality of push-pull successive phase modifiers, and the outputs of the phase modifier are connected by a passive component.
Abstract: Methods and apparatus for producing first and second drive signals from an input signal such that each drive signal is about 180 degrees out of phase with respect to the other; variably altering at least one of the first and second drive signals such that their respective magnitudes may be unbalanced to a varying degree; and producing an output signal from the first and second drive signals such that it includes harmonic distortion when the first and second drive signals are unbalanced.
Abstract: An operational amplifier with selectable performance characteristics is provided. The operational amplifier provides a sleep mode (e.g., fully disabled) in addition to providing a number of different levels of awake operation (e.g., different performance characteristics). As such, the op-amp can allow a system to use only the power needed to obtain a required level of performance at any point in time. For example, the op-amp may be operated at a minimum power mode, an awake at mid-level power mode, or an awake at maximum power mode.
Abstract: A transformer-coupled amplifier includes a driver transformer in which a primary winding, a secondary winding, and a tertiary winding are wound on a core of a magnetic circuit, a drive signal source for supplying an AC drive signal superposed with a drive-stage DC current to the primary winding of the driver transformer, a power tube for extracting, from the secondary winding of the driver transformer, an AC signal corresponding to the AC drive signal supplied to the primary winding of the driver transformer, and for amplifying the AC signal from the secondary winding, and a DC magnetization control power source for supplying a predetermined magnetization control current to the tertiary winding of the driver transformer so as to change a degree of DC magnetization of the core of the magnetic circuit of the driver transformer. The DC magnetized state of the core of the transformer magnetized by the DC current is appropriately changed by the magnetization control current.
Abstract: In an amplifier module circuit, an input transformer (TI) transforms an input signal (ISU) into a transformed input signal (ISB), which is supplied to a pair of amplifiers (AMPA, AMPB). In addition to windings (W1, W2) for input signal transformation, the core (CO) of the transformer (TI) is provided with an auxiliary winding (W3) for biasing the pair of amplifiers (AMPA, AMPB). A DC bias voltage (VB) is supplied to a tap (XT) on the auxiliary winding (W3) whose ends are DC coupled to the input transistors (QA, QB) of the pair of amplifiers (AMPA, AMPB).
Abstract: A high-power, high-fidelity tube amplifier which includes a plurality of output tubes connected in parallel with individual current sinks and a plurality of parasitic suppression components. Each current sink is electrically coupled to its corresponding output tube such that the output impedance of the current sink decreases as the grid current of the corresponding output tube increases.
Abstract: A phase inverter includes first, second, third and fourth terminals, a first coupling circuit coupled between the first and second terminals, a second coupling circuit coupled between the second and third terminals, a third coupling circuit coupled between the third and fourth terminals, and a fourth coupling circuit coupled between the first and fourth terminals. The first to fourth terminals and the first to fourth coupling circuits are arranged into a ring. The first coupling circuit is of a type different from a type of the fourth coupling circuit. The second and third coupling circuits are identical in type. Two output signals having a phase difference of 180.degree. are drawn from the second and fourth terminal when an input terminal is applied to the first terminal, and an output signal is drawn from the first terminal when two input signals having a phase difference of 180.degree. are applied to the second and fourth terminals.
Abstract: A fiber optic amplifier utilizes a crystal fiber of laser material to bidirectionally amplify light signals. This amplifier permits the application of both pumping illumination and the signal to be amplified to the end of the crystal fiber to avoid the disadvantages inherent in side pumping this fiber. End pumping is accomplished by taking advantage of the slow spontaneous fluorescence of the laser crystal to sequentially apply the pumping illumination and then the signal to be amplified to the crystal. This sequential application of signals is made possible through the use of a switchable coupler which allows light to be selectively coupled from either of a pair of input optical fibers to a single output optical fiber which is coupled to the crystal fiber. The pumping illumination is initially supplied to the crystal fiber to invert the ions within the crystal.
September 12, 1983
Date of Patent:
November 19, 1985
The Board of Trustees of Leland Stanford Junior University
Abstract: In a wide-band electronic AC amplifier, the first stage is direct coupled to a split load phase inverter which is RC coupled to a push-pull power output stage and the output is obtained through transformer coupling with a portion being returned to the cathode of the input stage as negative feedback. Instability (e.g., generation of high frequency "parasitics") is prevented by reduction of the effective impedance of the phase splitter, as seen by the control grids of the output tubes, by greatly lowering the resistance thereof. Since the triode is DC coupled to the pentode, the values of the load resistor and the screen dropping resistor in the pentode section must be reduced in order to increase the high frequency response and keep the current flow in the triode section within the maximum safe limits of the tube design.
Abstract: A protective coupling circuit is located between the D.C. supply voltage the amplifier components of a push-pull switching amplifier to suppress transients created during switching. The coupling circuit comprises a power supply filter with an inductor coil and capacitor, and circuitry for limiting the voltage on the individual switching elements and the output coil. Excess voltages caused by transients are fed to the power supply filter. In an alternative embodiment the power supply filter inductor coil is actually an auxiliary winding on the amplifier output transformer rather than a separate coil. This allows for use of some smaller capacity circuit elements.
July 15, 1976
Date of Patent:
September 6, 1977
The United States of America as represented by the Secretary of the Navy
Abstract: An audio amplifier in which an output stage is coupled by a driver stage to an input stage which includes two antiphased sources of alternating current. The output stage includes two pentode vacuum tubes each having a cathode, a plate and a screen grid located between the cathode and the plate. Each tube has a control grid connected between the cathode and the screen grid and a suppressor grid connected between the screen grid and the plate, with the control grid and the suppressor grid being shunted to their respective cathodes. The driver stage includes a pair of transistors connected in a push-pull configuration with their emitters connected to the screen grids of said tubes to supply a relatively high value of alternating current to the screen grids which function as control grids for their respective tubes.