Abstract: A pair of equivalent controlled impedance buffers are connected in a push-pull configuration to the primary coil of a transformer. A pair of equivalent pre-drivers are connected to the pair of buffers. Each pre-driver receives a driver input signal and outputs a buffer input signal and a flyback compensation signal proportional thereto. Each buffer receives the buffer input signal generated from one of the pre-drivers for buffered output as a line driver signal to the primary coil. A flyback voltage effect is induced in each buffer due to the line driver signal applied to the primary coil by the other buffer. Each buffer further receives the flyback compensation signal generated from the other one of the pre-drivers, with the buffer operating to cancel the flyback voltage effect induced in that buffer by the line driver signal applied to the primary coil by the other buffer using the flyback compensation signal received from the other one of the pre-drivers.

Abstract: The output signal converter for a tube amplifier includes semiconductor devices for amplifying or attenuating an output signal of the tube amplifier while maintaining output properties of the tube amplifier. The output signal converter in preferred embodiments has an output transformer (1) connected to the tube amplifier, a current amplifier and a voltage amplifier serially connected with each other via a node, and a speaker (4). The current amplification factor (Ac) of the current amplifier (2) and the voltage amplification factor (Av) of the voltage amplifier (3) are related according to the following equation: Ac*Av=−k, wherein k is a constant.

Abstract: An impedance matching and filter network is disclosed. The network performs two preselected impedance transformations and provides a filtering function to attenuate harmonics of an electrical signal delivered at an input of the network. The network may advantageously be structured in the form of balanced dual filters which are referenced to a virtual ground between them, the virtual ground being connected to a shield which surrounds the electric components. The network is particularly suitable for use with electrodeless discharge lamps to provide an impedance matching function for the induction coil and to limit RFI.

Abstract: An analog line connection circuit provides that the transmission voltage is not superimposed on the received voltage given a data transmission in duplex operation via a two-wire line. The line connection circuit is provided with an amplifier that comprises two symmetrical outputs, the first of these outputs being connected via a first ohmic connecting resistor to a first terminal of a first winding of a transformer and the second output being connected via a second ohmic connecting resistor to a second terminal of the first winding of the transformer. The transformer comprises a second winding connected to a transmission line. A series circuit of a first auxiliary resistor, a complex impedence and a second auxiliary resistor is connected between the outputs of the amplifier.

Abstract: A line driver for a cable linked LAN maintains a high impedance across the cable when not sending data. A pulse transformer includes a primary and secondary winding. The primary winding of the transformer is placed between a first pair of transistors and a second pair of transistors. An array of switching inverters activates these transistors in such a manner whereby, when one pair is turned on, the other pair is turned off. This "off" and "on" toggling of the transistor pairs drives current into the transformer primary. Such current induces a pulse in the transformer secondary which is coupled into the LAN cable.

Abstract: A transformer-based coupling network permits a push-pull amplifier to be used with single ended signals, while providing constant gain and, if desired, bidirectional impedance matching, from RF down to DC.

Abstract: Intermodulation distortion in RF FET amplifiers operating in the Class AB mode is reduced without limiting the bandwidth by providing transformer coupled outputs from both the source and drain circuits. The negative feedback provided by the transformer in the source circuit reduces distortion but does not limit bandwidth in the manner of the reactive network normally used for correct phasing in circuits employing drain to gate feedback. Using this technique, the distortion components are typically 40-45 dB below the desired signal when a two-tone test is used, which exceeds the typically available level of 30 dB in prior art circuits.

Abstract: A low-level, low-power radio frequency (RF) communications system designed to operate as a point-to-point power line communications sytem (PLC) utilizing frequencies from 50 to 600 MegaHertz (MHz) superimposed onto the AC power signal in a building.

Abstract: A transformer isolated high voltage, high power system is disclosed which is suitable for driving servo motors in servo loop control systems or the like. A D.C. current control loop is provided for preventing transformer saturation without gapping the transformer core. An output control loop is provided which minimizes signal crossover distortion and input/output phase shift. Crossover distortion adjustment is also implemented.

Abstract: A low-distortion transformer-coupled circuit. An amplifier is constructed to have a negative output impedance equal to the resistance of the primary winding of a coupling transformer to which the amplifier is connected thereby cancelling the distortion component produced by the transformer distortion current flowing through the primary winding resistance. The input to the amplifier is thus coupled to the secondary winding of the transformer. A low-frequency feedback circuit is provided between the amplifier output and a non-inverting input thereof. Means is provided for adjusting the negative output impedance of the amplifier to match circuit parameters. Alternatively, the coupling transformer employs two matched primary windings and one secondary winding, and the amplifier is constructed to provide a signal to each primary winding.

Abstract: A converter circuit receives N-rail logic signals and converts them into a precision N-level signal. A pair of line drivers is connected in a balanced output arrangement with the primary winding of an output transformer. In response to the N-rail logic signals, weighted currents are conducted through an input impedance, connected with the line drivers, to a ground reference. As a result the line drivers conduct various levels and polarities of current through the entire primary winding of the output transformer. Thereby a precision N-level signal is produced in a secondary winding of the output transformer and at the converter output terminals.

Abstract: A current branching circuit for an amplifier for first and second input terminals and a current supply feed terminal comprising a pair of magnetically coupled windings with one of the windings connected between the center conductor of a coaxial feed line and one of the input terminals and the other windings connected between the other input terminals to a capacitor which has its other side connected to the outer conductor of the coaxial line and wherein the pair of leads connecting the pair of windings to the pair of input terminals cross one another. The outer conductor of the coaxial line is connected to the current supply feed terminal through a second capacitor.

Abstract: The collectors of a pair of transistors operated quasi-linearly in push-pull are coupled to their load by an autotransformer winding, center-tapped to receive operating potential. The configuration simulates a full-bridge amplifier with operating potential twice as large, insofar as maximum output power capability is concerned.

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 pair of complementary output transistors having common connected emitters and a primary winding of a transformer in each of the collector circuits, said transistors being biased in class AB operation with a drive transistor connected to the base thereof and a feedback circuit, including both AC and DC, connected from the common emitters to the input of the drive transistor so that the quiescent current of the amplifier is very low and the output impedance is high.

Abstract: A frequency tunable microwave apparatus including a semiconductor TRAPATT diode generating a microwave signal at its fundamental, second and third harmonic frequencies. Energy is extracted at the second harmonic frequency and a certain impedance loading is provided at the fundamental frequency and third harmonic by a variable impedance hybrid idler circuit. The hybrid idler circuit comprises a distributed transmission line serially connected to a lumped variable capacitor. Variations in the capacitance of the variable capacitor tune the fundamental frequency without substantially varying the impedance loading conditions of the diode allowing energy to be extracted at the second harmonic frequency throughout the tunable frequency range.

Abstract: An R. F. wide band amplifier is disclosed. It comprises a high impedance step up transformer at the input end, a wide band high impedance J-Fet attenuator connected to the step up transformer, a dual gate MosFet amplifier connected to the attenuator and a high impedance wide band step down transformer connected to the output of the MosFet. The output of the amplifier is taken from the stepped down side of the transformer.

Abstract: An audio amplifier with a transistorized power output stage furnishes an amplified audio signal to an autotransformer. The autotransformer has a plurality of taps to permit the selection of any of a plurality of output impedance levels. The autotransformer is wound on a bobbin in a novel manner so as to minimize distortion of the audio signal.