Abstract: A multi-channel output device for a multimedia device includes a plurality of reception ends, an amplifier having an input end and an output end, a plurality of sound output devices for outputting sound, a first switching unit coupled between the plurality of reception ends and the input end of the amplifier for coupling a reception end of the plurality of reception ends to the input end of the amplifier according to a control signal, a second switching unit coupled between the output end of the amplifier and the plurality of sound output devices for coupling the output end of the amplifier to a sound output device of the plurality of sound output devices according to the control signal, and a control unit coupled to the first switching unit and the second switching unit for outputting the control signal.

Abstract: The present invention relates to an amplifier arrangement having a plurality of amplifier stages that form a series circuit. Each amplifier stage comprises a current mirror, the translation ratio of which defines the gain of the amplifier stage. Moreover, a current coupling-out element is provided in each amplifier stage, a partial current being output at said element, and the partial currents are added together in a summation element. An RSSI signal associated with the summed currents is provided at the output of the summation element. The RSSI amplifier arrangement provides constant and thermostable signal amplification, low sensitivity to overvoltages, and exhibits a low current requirement and good radio frequency properties.

Abstract: A novel drive stage provides with low distortion a large amplitude signal, such as required for driving a cathode-follower output stage of a power amplifier. The drive stage comprises an amplification substage and a load substage. Each substage comprises two series connected vacuum tubes. Each substage is provided with a respective voltage divider network to provide that the two tubes of each substage share approximately equally both the quiescent static voltage and the dynamic voltage of the substage. The load substage coacts with the amplification substage to provide a novel mu-follower or SRPP circuit having approximately twice the voltage swing of a conventional circuit. This approximately quadruples the maximum power output of the cathode-follower amplifier.

Abstract: A radio frequency amplifier includes a first amplifier stage having a first transistor, and a second amplifier stage having a second transistor. The first transistor has a base input for receiving an input voltage, a collector output, and an emitter coupled to a common. The second transistor has a base input coupled to the first transistor collector output, a collector output, and an emitter coupled to the common by a resistance element. The second transistor emitter is DC coupled to the first transistor base. The DC coupling of the first transistor base to the second transistor emitter provides stable DC biasing of the first and second transistors based on base-emitter voltages of the first and second transistors. The radio frequency amplifier may be employed in a variety of receiver/amplifier applications, such as vehicular driver integrity check systems.

Abstract: A cathode-follower power output stage is driven by a novel drive stage to provide with low distortion the large signal required to drive the output stage. The drive stage comprises two series connected vacuum tubes which share the large static and dynamic voltages of the drive stage so as to provide a drive signal having a large voltage swing, without generating audible distortion and without subjecting the drive stage tubes to excessively high voltages. The plate of a first drive tube is connected to the cathode of the second drive tube. A load impedance is connected from a B+ power supply terminal to the plate of the second drive tube. The grid of the second drive tube is driven by a signal responsive voltage divider network driven by the plate of the second drive tube.

Abstract: In an amplifier using at least two transistors are amplifying elements, the bases (or gates) and the collectors (or drains) of the transistors are commonly connected. A first impedance element is connected between the bases (or gates) and the collectors (or drains). A second impedance element is connected between an emitter (or source) of each transistor and a ground. A third impedance element is connected between the emitters (or sources).