Abstract: A bone conduction speaker includes a housing, a vibration board and a transducer. The transducer is located in the housing, and the vibration board is configured to contact with skin and pass vibration. At least one sound guiding hole is set on at least one portion of the housing to guide sound wave inside the housing to the outside of the housing. The guided sound wave interfaces with the leaked sound wave, and the interfacing reduces a sound pressure level of at least a portion of the leaked sound wave. A frequency of the at least a portion of the leaked sound wave is lower than 4000 Hz.

Abstract: A radio-frequency module includes duplexers and a phase circuit. A first transmitting-signal input terminal is connected to the duplexer, while a second transmitting-signal input terminal is connected to the duplexer. The phase circuit is connected between the first transmitting-signal input terminal and the duplexer. The phase circuit performs phase adjustment so that impedance matching between the first transmitting-signal input terminal and the duplexer is performed in the fundamental frequency band of a first transmitting signal, and so that the phase of the frequency band of a second transmitting signal in relation to the impedance characteristics of a first transmission path which ranges from the first transmitting-signal input terminal to the duplexer with the phase circuit provided therebetween appears in an open side on a Smith chart.

Abstract: The present invention relates to a method and apparatus for feeding back, by a terminal, reference signal information in wireless communication using a two-dimensional active antenna system including a plurality of antennas. Particularly, the method for feeding back reference signal information comprises the steps of: receiving, from a base station, a reference signal configuration including identifiers of a plurality of reference signals having a first reference signal set and a second reference signal set; receiving the plurality of reference signals to which the precoding is applied; measuring reference signal received power (RSRP) for each of the plurality of reference signals; and transmitting, to the base station, information on at least a part of the first reference signal set and information on at least a part of the second reference signal set, on the basis of the measured RSRP.

Abstract: A hearing assistance system includes an adaptive binaural beamformer based on a multichannel Wiener filter (MWF) optimized for noise reduction and speech quality criteria using a priori spatial information. In various embodiments, the optimization problem is formulated as a quadratically constrained quadratic program (QCQP) aiming at striking an appropriate balance between these criteria. In various embodiments, the MWF executes a low-complexity iterative dual decomposition algorithm to solve the QCQP formulation.

Abstract: A hi-fi headphone device with two speakers, an integrated pentode vacuum tube, and a battery. The battery is electrically connected to direct and bias circuits, to provide proper voltage to the vacuum tube amplifiers, wherein input signal is amplified and output to buffer circuits and impedance is matched between the tube and output speaker terminals.

Abstract: An information handling system power supply dynamically adapts thermal and power output protection constraints based upon thermal and power output conditions measured at the power supply. In the event of changing conditions at the information handling system, such as an increase in ambient temperature or an increase in power consumption, a power constraint adaptive module adjusts constraints at which the power supply will shut down in order to maintain power to an information handling system outside of a normal power and thermal constraint operating envelope for the power supply.

Abstract: A power amplifier (power amplifier) having multiple solid state sub-amplifiers connected in parallel between the power amplifier input and the power amplifier output are described. The signal input to the power amplifier is provided to an RF splitter connected between the power amplifier input connector and the input of each of the sub-amplifiers The RF splitter splits the input power from the signal input and provides the power to the sub-amplifier inputs through input electrical paths. The input electrical paths from the power amplifier input to the sub-amplifiers are substantially physically identical. Each of the sub-amplifiers drive an input of an RF combiner connected between the outputs of the sub-amplifiers and the output of the power amplifier. The RF combiner combines the output power from each of the sub-amplifiers through output electrical paths, and provides the combined power to the power amplifier output.

Abstract: A bidirectional amplifier circuit includes first and second input ports, first and second output ports, a power amplifier, and first, second, third, and fourth filter circuits. The power amplifier includes at least first and second input terminals and first and second output terminals. The first filter circuit is coupled between the first input port and the power amplifier first input terminal. The second filter circuit is coupled between the second input port and the power amplifier second input terminal. The third filter circuit is coupled between the first output port and the power amplifier first output terminal. The fourth filter circuit is coupled between the second output port and the power amplifier second output terminal. Carrier waves of differing frequencies may be injected into the amplifier circuit first and second input ports, and transmitted from the first and second output ports.

Abstract: An audio boost circuit having an input buffer responsive to a program input signal for providing a buffered program signal, An all pass phase inverter having an input coupled to receive the buffered program signal and an output providing an inverted buffered program signal. A band pass filter having a predetermined Q, responsive to the buffered program signal for providing an inverted band pass boosted program signal. A summing amplifier for adding the inverted buffered program signal to the inverted band pass boosted program signal and for providing a composite program signal signal. A frequency adjustment means for adjusting the frequency at which the peak gain occurs. The input buffer is a state-variable input filter that processes the program input signal into high, low and mid-range frequency signal components. The input buffer has gain control circuitry for balancing and summing the high and mid-range signal components.

Abstract: Disclosed is a thermal protection circuit for an amplifier generating an amplified AC output signal. The thermal protection circuit may be powered by an amplifier power supply used to power the output stage. The amplifier power supply may be referenced to ground. The thermal protection circuit includes a power conditioner for providing regulated power rails to the other components of the thermal protection circuit. The regulated power rails may be referenced to the amplified AC output signal.

Abstract: A power amplifier including: a first amplifier PA2 having an input terminal and an output terminal; a passive circuit PC3 having an input terminal and an output terminal; and a first switch SW2 having a single-pole terminal and two multi-throw terminals, one of the multi-throw terminals of the first switch SW2 being connected to the input terminal of the first amplifier PA2 and the other of the multi-throw terminals of the first switch SW2 being connected to the input terminal of the passive circuit PC3. This makes it possible to provide a power amplifier and a communication unit which can be operated with different frequencies, output powers or modulation types.

Abstract: Sag of a power signal delivered to of an amplifier is controlled. The maximum amount of sag is limited to limit crossover distortion. A measuring circuit monitors an observed signal to generate a measured signal. A sag control circuit receives the measured signal and one or more input control signals, and in response generates a sag control signal. A regulator circuit receives the sag control signal and a raw power supply signal and in response generates a regulated DC power supply signal for the amplifier. The regulator circuit decreases the maximum power available to the amplifier as the sag control signal magnitude increases, so as to increase distortion and compression in the output signal (e.g., and achieve a "warm", "airy" or "forgiving" sound quality resembling or improving the sound of a vacuum tube amplifier).

Abstract: A regulated power supply control system with adjustable operating point and adjustable dynamic behavior for use with electronic power supply circuits, such as musical instrument amplifiers. The control system includes a measurement circuit (20) that generates a measured signal (22) based on an observed signal (18) in an amplifier (10); a sag control circuit (24) that generates a sag signal (32) based on the measured signal (22); a referenced circuit (34) that generates a static reference signal (38); and a regulator (44) that uses the static reference signal (38) and sag signal (32) to generate a regulated power supply output (14) that is used by the amplifier (10). The sag control circuit (24) permits adjustment of the sag signal 32 by a user-operated sag magnitude control (26), sag rate control (28), and sag recovery rate control (30).

Abstract: A method enables a musician to reduce the voltage level between a nominal level which is supplied to power an audio power amplifier including at least one vacuum tube power output device and a reduced level, by controlling AC input voltage level of an AC to DC power supply via an input transformer having a primary winding connected to receive nominal AC voltage from the AC power mains, a high voltage secondary, and a low voltage secondary for directly supplying heater power to the vacuum tube power output device.

Abstract: The power supply potential applied to the final stage of an RF amplifier is odulated by means of an adaptive power supply. The power supply potential applied to the final RF amplifier is controlled by a first control loop in accordance with an error signal derived from a comparison of a signal corresponding to the weighted sum of the magnitude of the supply voltage applied and the current drawn by the final amplifier and the amplitude of the modulating signal. Additionally, an automatic level control circuit controls the level of the RF output signal in a second control loop in accordance with a comparison between the magnitude of the RF output of the amplifier and the amplitude of the modulating signal.

Abstract: An audio system including audio processing circuit means interposed between a source of audio signals and a power amplifier. Power control circuitry including time delay means which respond to an on/off power switch for applying and removing power to the components of the audio system in a sequence which prevents audible pops associated with system start-up and shutdown.

Abstract: A circuit which allows for the simultaneous control of the bias voltages applied to the screen grids and control grids of output tubes while maintaining the ratio of said voltages, thereby providing a method for selectively varying a single plate characteristic (Power Output) of a tetrode/pentode vacuum tube.In the case of musical instrument amplifiers, it is a desirable effect to drive the power amplifier (output stage) beyond the point that said power amplifier is able to reproduce its input signal accurately, hence causing output distortion. Said point is known as the "Clipping Point".A clipping point is most usually achieved at high sound pressure levels which are uncomfortable and difficult to work under. By varying said voltages in the previously stated manner, one varies the clipping point accordingly, and therefore is able to obtain output distortion at variable sound pressure levels.

Abstract: A nonlinear signal transducer U, such as a light-emitting diode or a semiconductive laser, is maintained at a suitable operating point by a constant biasing current and receives an electrical input signal by way of a series resistor R from a main amplifier AM of variable gain. The output voltage of the main amplifier is detected and integrated to provide a first reference voltage which is compared with the load voltage of the transducer U in a differential amplifier AE1, forming part of a first feedback loop, to adjust a voltage generator GT controlling the output voltage of the main amplifier AM so as to eliminate any voltage drop across the series resistor R as long as the input signal is absent or has an instantaneous magnitude equal to its mean value.

Abstract: A method and apparatus for monitoring and controlling the anode power dissipation of transmitters. First and second signals proportional to the anode power input and anode power output are produced and subtracted from each other, thus resulting in a third signal proportional to anode power dissipation. The third signal is applied to a pair of threshold value actuators, with one threshold value actuator actuating transmitter tuning elements when an initial threshold level is exceeded, and the second threshold actuator switching the transmitter off when a second threshold is exceeded.

Abstract: A circuit arrangement for combining high frequency power components with the same frequency which come from amplifiers or generators and are fed to a 90.degree. parallel circuit bridge having two substantially decoupled inputs with the input resistance values of these inputs depending on the output load. The operating voltage supplies of the amplifiers or generators are separately controllable and are controlled so that the output powers of these amplifiers or generators, respectively, remain substantially constant even with mismatching.