Abstract: A beam forming antenna in which directivity directions of beams can be controlled at higher resolution of control is provided. The beam forming antenna includes a matrix circuit having multiple final output terminals and multiple antenna elements connected to the multiple final output terminals respectively. The matrix circuit includes a first sub-matrix, a second sub-matric, and adders which combine outputs of the first sub-matrix and outputs of the second sub-matrix. By selecting any input terminal out of the multiple input terminals of the first sub-matrix or the multiple input terminals of the second sub-matrix and inputting a signal, a signal having a predetermined phase difference between output terminals is output at the multiple final output terminals and the phase difference between output terminals has a differing value according to a selected input terminal.

Abstract: Disclosed is a configurable dual vacuum tube triode amplifier. The amplifier comprises two vacuum tube triodes and a user configurable switching component. The user configurable switching component can be positioned into at least a first position and a second position to modify an arrangement of the two vacuum tube triodes to provide varying tonal characteristics of the amplifier. Positioning the user configurable switching component in the first position arranges the two vacuum tube triodes in a cascode configuration to achieve a tonal characteristic of a vacuum tube pentode. Positioning the multi-position user switch in the second position arranges the two vacuum tube triodes in either a single vacuum tube triode configuration to achieve a tonal characteristic of a single vacuum tube triode operating alone or two vacuum tube triodes operating in a parallel configuration to achieve the tonal characteristics of two vacuum tube triodes operating in parallel.

Abstract: The present invention provides a device with rear-mounted vacuum tubes, comprising a protective cover with a plurality of heat dissipating holes, a rear panel with a panel opening, and at least one vacuum tube, wherein the vacuum tubes are arranged in a containing space of the protective cover through the panel opening and inserted to a connection circuit board for coupling to a printed circuit board. In addition, the protective cover, the rear panel, and the vacuum tubes are placed in parallel with the printed circuit board, so that heat dissipation for the device is improved and replacement and maintenance of the vacuum tubes are easier. In particular, a vacuum tube audio amplifier apparatus having the device with rear-mounted vacuum tubes as disclosed herein can be stacked.

Abstract: The present invention provides a vacuum tube audio amplifier which includes an audio pre-amplifying portion and an audio output transforming portion. The audio pre-amplifying portion includes an equalizer for enhanced sound quality and amplifies an audio signal, which is subsequently transmitted to the audio output transforming portion. Furthermore, the audio output transforming portion includes an audio output transformer which includes a plurality of stacked E-shaped silicon steel sheets and a plurality of stacked I-shaped silicon steel sheets, wherein the stacked E-shaped silicon steel sheets and the stacked I-shaped silicon steel sheets have a same height which is smaller than or equal to 48 mm.

Abstract: Provided is an impedance conversion circuit of a condenser microphone which includes a first electron tube operated in grounded-cathode mode to whose grid an output signal from a condenser microphone unit is inputted, and from whose plate a signal is outputted, a first emitter-follower circuit configured to receive a signal based on a plate output of the first electron tube and amplify a current, and a first feedback element configured to transmit a feedback signal from an emitter of a transistor configuring the first emitter-follower circuit to the grid of the first electron tube. And the impedance conversion circuit can achieve a wide dynamic range while using a voltage amplifier circuit with an electron tube at an initial stage.

Abstract: To provide an impedance converter circuit for a condenser microphone which can secure a wide dynamic range using a voltage amplifier circuit. The impedance converter circuit is provided with: a first electron tube of a cathode grounded type in which an output signal of a condenser microphone unit is input into a grid and output from a plate; a second electron tube in which an output signal from the plate of the first electron tube is input into a grid and output from at least a cathode; and a feedback element configured to transmit a feedback signal from the cathode of the second electron tube to the grid of the first electron tube.

Abstract: In accordance with an embodiment, a voltage controlled oscillator (VCO) includes a VCO core having a plurality of transistors, a bias resistor coupled between collector terminals of the VCO core and a first supply node, and a varactor circuit coupled to emitter terminals of the VCO core. The bias resistor is configured to limit a self-bias condition of the VCO core.

Abstract: The application discloses a multi-input DC converter and a PFC circuit. The multi-input DC converter of the application includes n diodes, a transformer, a switching transistor, a rectifier and filter circuit, and a load. The transformer includes a primary winding and a secondary winding, the number of turns of the primary winding is N1, and the primary winding is divided into n sections by leading out n?1 taps in a specific manner; anodes of the n diodes are respectively connected to n input sources in turn, cathodes of the n diodes are respectively connected to a first terminal of the primary winding and n?1 tap terminals in turn, a second terminal of the primary winding is grounded through the switching transistor, and the secondary winding delivers energy to the rectifier and filter circuit and then to the load. The structure is simple, and the cost is low.

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: A power amplifier includes an amplifying circuit, and first through third transmission lines. The amplifying circuit amplifies an input signal having a fundamental frequency to generate a first amplified signal and a second amplified signal whose phase is opposed to the first amplified signal. The first transmission line adds a first group of phases, different in correspondence with a frequency, to the first amplified signal by using a left-handed material to generate a first transmission signal. The second transmission line adds a second group of phases, different in correspondence with a frequency, to the second amplified signal by using a right-handed material to generate a second transmission signal. The third transmission line overlaps the first and the second transmission signals to generate an output signal. The first and the second group of phases include a phase difference configured to weaken a second harmonic and a third harmonic.

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.

Abstract: A tuner, a broadcast signal processing apparatus and method, which satisfy reception sensitivity of both terrestrial and cable televisions, when selecting a broadcast signal through a single conversion tuner, are provided. A tuner selects a broadcast signal of a selected channel. The tuner includes an input filter that filters a received broadcast signal into plural frequency bands based on a predetermined frequency band. An amplifier amplifies a second signal having an original phase induced by an output signal of the respective frequency bands, and a first signal having an opposite phase of the second signal, and outputs the signal induced by the amplified first and second signals as an amplification signal of the signal in the respective frequency bands. An inter-stage filter filters a frequency of the broadcast signal corresponding to the selected channel among the amplification signals output from the amplifier.

Abstract: A power supply for a guitar amplifier and the guitar amplifier and method of operating the guitar amplifier. The power supply includes an alternating current power input having a secondary winding and a filament winding, an output and a first vacuum tube rectifier coupled between the secondary winding of the power input and the output for rectifying the alternating current at the power input. At least a second rectifier is provided which is selectively couplable in parallel with the first vacuum tube rectifier. The at least one second rectifier can be a vacuum tube rectifier with each of the first and second rectifiers having a cathode continually energized by the filament winding, a solid state rectifier or both. The output amplifier has an output transformer having a primary winding with a center tap and with a first pair of vacuum tube amplifiers having their cathodes being coupled together and their plates coupled to the primary winding on opposite sides of the center tap.

Abstract: An amplifier is described including a pair of cathode-coupled pentode vacuum tubes. A first pentode of the pair includes a control grid configured to receive an input signal. A second pentode of the pair includes a control grid configured to be coupled to an input reference signal. A cascaded voltage regulator includes a first stage configured to generate a plate reference voltage for providing voltage to a plate of each pentode. The regulator includes a second stage configured to generate a screen reference voltage based on the plate reference voltage for providing voltage to a screen grid of each pentode. The amplifier can also include a push-pull output stage having a servo circuit configured to adjust the control bias signal for one of a pair of vacuum tubes included in the stage until the plate currents in the pair of tubes are substantially equal.

Abstract: A Class D amplifier device with reduced power consumption uses a passive RC network. The output of the RC network directly feeds a comparator resulting in increased efficiency. The RC network is configured to perform several functions, including the low pass filtering of the feedback signal to remove high frequency/high amplitude clock components and provides a DC path from its output to reduce duty cycle errors. Additionally, the input signal receives low pass filtering, creating a generally flat frequency response. Finally, the clock signal is filtered to generate a triangle wave of good linearity and appropriate amplitude.

Abstract: A power supply for a guitar amplifier and the guitar amplifier and method of operating the guitar amplifier. The power supply includes an alternating current power input having a secondary winding and a filament winding, an output and a first vacuum tube rectifier coupled between the secondary winding of the power input and the output for rectifying the alternating current at the power input. At least a second rectifier is provided which is selectively couplable in parallel with the first vacuum tube rectifier. The at least one second rectifier can be a vacuum tube rectifier with each of the first and second rectifiers having a cathode continually energized by the filament winding, a solid state rectifier or both. The output amplifier has an output transformer having a primary winding with a center tap and with a first pair of vacuum tube amplifiers having their cathodes being coupled together and their plates coupled to the primary winding on opposite sides of the center tap.

Abstract: A fiber-to-the-home (FTTH) system transmits forward and reverse optical signals, such as video, voice, and data signals, via optical fiber, and includes a plurality of home network units. The home network units include an FTTH optical receiver for receiving at least one of the video, voice, and data signals. A triplexer distinguishes and separates the video, voice, and data signals, wherein the video signals have a first wavelength and the voice and data signals have a second wavelength. The voice and data signals are provided to the home network unit for further processing. The triplexer provides an electrical signal to the amplifier stages. The amplifier stages include a preamplifier stage and a postamplifier stage. A gain control circuit automatically adjusts the gain of the video signal based upon the input power level to the FTTH optical receiver. Additionally, a tilt network performs level compensation for externally located coaxial cable.

Abstract: A hybrid thermionic valve and solid state audio amplifier. A complete tube amplifier is scaled to produce a relatively low power yet also retain its small and large signal distortion characteristics. The output of the scaled amplifier is amplified by a relatively linear solid state amplifier. In one embodiment of the invention, a plurality of tube amplifiers are coupled in parallel and input to a mixing circuit for selectably mixing the outputs of the tube amplifiers and providing the mixed outputs to the solid state amplifier.

Abstract: In a direct coupled type vacuum tube amplifying circuit, to stabilize the operation and simplify the feedback loop, a plate power source EB5 is connected to a plate of a vacuum tube V5 of a first stage through a constant current source 1. A grid of a vacuum tube V6 of a next stage is connected to the plate of the vacuum tube V5 through a first resistance R3. A second resistance R4 is connected between the grid and the cathode of the vacuum tube V6. A negative power source EC6 is connected to the resistance R4 through a constant current source 2. In this constitution, the grid bias voltage of the second vacuum tube V6 is defined by the voltage drop of the second resistance R4.

Abstract: An apparatus and method for reducing errors in a battery powered sensing circuit uses two pull-up resistors. The first resistor has a value selected to minimize battery drain and the second resistor has a value selected to reduce dendrite or other parasitic parallel resistance. The resistors are selectively connected to the circuit based on a predetermined sequence and/or time interval.

Abstract: An electronic amplifying apparatus for sound reproduction and musical instrument amplification including at least two pairs of power output devices which are independently switchable between triode and pentode operation. The amplifier further contains a switch apparatus to select the amount of negative feedback within the amplifier.

Abstract: A power amplifier has a distortion control circuit responsive to a clipping detector for loading said amplifier input with a signal sufficient to reduce the input to the tube grids to a level below clipping.

Abstract: A phase-locked loop (or frequency-locked loop) based circuit for controlling the drive applied to a DC polyphase motor is disclosed. The disclosed circuit includes a clamp circuit, connected to the input of the motor drive amplifier, for limiting the current applied to the drive amplifier, in order to ensure that the power supply is not overloaded. According to one embodiment of the invention, the clamp circuit includes a buffer amplifier having a source leg and a sink leg. During a current control mode, both the source leg and sink leg of the buffer amplifier are enabled to drive the input of the motor drive amplifier; the buffer amplifier is a differential amplifier and applies a feedback signal from the drive amplifier input to control the current applied thereto according to an input limit signal.

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: An electronic circuit provides a linear output from an amplifying device, such as a hybrid push-pull amplifier, which has inherent distortion. In a preferred embodiment, the distortion of the hybrid amplifier is compensated by nesting a pair of hybrid push-pull amplifiers within a push-pull circuit configuration. In another embodiment, the distortion of the hybrid amplifier is compensated by providing a predistorted signal equal in magnitude, but opposite in sign, to the distortion introduced by the nonlinear device. The input signal is split into two electrical paths with the primary part of the signal applied directly to the hybrid amplifier, with a time delay to compensate for delay in the secondary path. Elements within the secondary path generate both even and odd order distortion products. These are recombined with the primary signal in proper phase and amplitude, and the resulting signal is applied to the hybrid amplifier for canceling distortion in the hybrid amplifier.

Abstract: A high-performance, distortion-free, audio push-pull amplifier has a class A driver stage that drives a class B push-pull output stage that is coupled to a load through a transformer that has a center tap primary with screen taps. The driver tube cathodes are coupled to the output tube grids. The driver tube plates are tied to the screen taps on the output transformer primary. These taps are also coupled to the output tube screen grids. At low power levels the driver stage drives the load through the output transformer. As power level rises the power stage supplies more and more of the output power. This circuit avoids notch or crossover distortion at low power levels.

Abstract: The present invention is an audio frequency power amplifier input circuit having improved vacuum tube circuit topology. The improved circuit includes a direct current feedback circuit within the input circuitry which stabilizes the operating point of a phase inverter. The feedback circuit maintains optimum operation of the circuit despite variations in tube characteristics or supply voltages. Another aspect of the improved circuit comprises a low impedance phase inverter which improves the drive capability of the phase inverter to push-pull power output vacuum-tube grids.

Abstract: The present invention provides a modified distributed amplifier which is capable of providing push-pull operation without the loading losses of conventional push-pull combining. The modified distributed amplifier comprises a distributed amplifier configuration and with signal inverting means, such as a wide bandwidth transmission line transformer, interconnected into both the input and output lines. The signal inverting means are most effectively placed at the electrical centers of the lines, but may be placed at any positions in the individual lines to produce optimum performance to specific applications. The separate segments of the distributed amplifier separated by the signal inverting means operate in opposed phase but the signals output to the load add in phase thus providing push-pull operation.

Abstract: The invention relates to a high frequency amplifier for coupling a load with a tetrode which is used as the amplifier tube and which is provided with a regulating circuit with a set point adjuster for the anode voltage. The regulating circuit can also be influenced by a control variable as the set point feedforward which is dependent on the tetrode screen grid current and which is used for automatically matching the anode voltage to the operating conditions of the load. For the power dissipation of the screen grid and anode of the tetrode, a regulating circuit can be provided with a limitation of the controlling high frequency power dependent on the screen grid current.

Abstract: A vacuum tube amplifying apparatus provides predetermined varying dynamic response characteristics in order to enhance the playing characteristics of musical instruments, especially guitar.

Abstract: A variable power amplifier having a constant current differential amplifier driving a cascaded driving amplifier, a variable power amplifier including a vacuum tube for selectively amplifying output signals wherein the drive of the variable power amplifier is determined by the plate shunt resistive loading of the vacuum tube, a push-pull amplifier including an output transformer operatively coupled to the variable power amplifier and to an amplifier output terminal to amplify and apply to the amplifier output terminal a selectively amplified output signal, and a variable damping circuit including a sensing element for sensing the loading on the output tranformer and a circuit for defining a feedback loop for producing a feedback signal having magnitude and polarity which are determined by the sensing element and wherein the variable damping circuit includes a circuit for applying the feedback signal as an input to the constant current differential amplifier to control the current level thereof as a function o

Abstract: A push-pull microwave amplifier in which an input signal is split into two ransmission paths in a manner which simulates the behavior of a center-tapped transformer over a broad frequency range. The input signal is first divided into two identical paths and then passed down first and second transmission line segments in the two paths bi-directionally. One of the transmission line segments is terminated in an open circuit and the other in a short circuit so that the reflected signals have the opposite polarities. By making the transmission line segments of equal length, the opposite polarity signals emerge from the transmission line segments at the same time. The signals are then amplified and then passed again bi-directionally along third and fourth transmission line segments terminated in short and open circuits so as to re-convert the signals to the same polarity. The signals are then summed to produce the composite amplified output signal.

Abstract: A distributed amplifier is provided with an output filter line with the output terminals of a plurality of individual amplifying devices connected to different points along the output filter line. Instead of dimensioning the impedance of the output filter line to provide a perfectly uniform frequency response, it is arranged as a wide band multiple quarter wave impedance transformer. The use of this kind of output filter line provides superior performance when the amplifier is used with mismatched loads and the frequency response can still be very good.

Abstract: This invention provides a method and means for amplifying signal waves with high efficiency that comprises signal sampling means operating at the Nyquist rate or greater, sample-quantizing means, a plurality of circuits that link the quantizing means to a plurality of controlled current-switching means, combining means that combines the outputs of the plurality of switching means, and filter means that reconstructs an amplified facsimile of the signal.

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.

Abstract: A drive circuit responsive to the phase of the amplifier output current eres that the non-conducting amplifier element remains off while the other amplifier element conducts. The output current phase can be detected either from the individual amplifier element outputs or from their combined outputs. Adjustments are made to compensate for any phase shift which occurs between the input to the amplifier and the point in the output at which the phase is detected.