Abstract: An amplifying circuit arranged for converting an input signal into an amplified output signal comprising: an input node (11) at an input side of said circuit for receiving said input signal (pi); an output node (9) at an output side of said circuit for outputting said amplified output signal (io); a first gain element (M1) connected between said input and output nodes and provided for converting an input voltage taken from said input signal into a current for forming said amplified output signal; a negative feedback loop (3) over said first gain element, said negative feedback loop having first elements (5, 6) arranged for providing input matching; and a positive feedback loop (2) over said first gain element, said positive feedback loop having second elements (7, 8) arranged for providing additional input matching and gain enhancement of said first gain element.

Abstract: A modulation device includes a signal input for receiving a data stream to be modulated and a first and a second signal output. At least one first complex component is derived from the data stream in a coding device. A first and a second high-frequency signal are output via the signal outputs. The first and second high-frequency signals are derived from the at least one first complex component and are distinguished by the fact that the second high-frequency signal has a phase shift of substantially 90° with respect to the first high-frequency signal.

Abstract: Systems and methods are provided for positive and negative feedback of cascode transistors for a power amplifier. The systems and methods may include a first cascode stage comprising a first common-source device and a first common-gate device; a second cascode stage comprising a second common-source device and a second common-gate device; a first degenerative element or block provided for the first common-source device; a second degenerative element or block provided for the second common-source device; a first positive feedback block or element that connects a first gate of the first common-source device with a second drain of the second common-source device; and a second positive feedback block or element that connects a second gate of the second common-source device with a first drain of the first common-source device.

Abstract: The present invention provides an amplifier circuit comprising a differential amplifier and a negative feedback loop circuit, in which a positive feedback loop circuit having a gain smaller than a gain of the negative feedback loop circuit is formed inside the negative feedback loop circuit.

Abstract: An audio amplifier including a series connected vacuum tube output stage for driving an audio loudspeaker. The preferred amplifier uses the output signal as a floating reference for an intermediate stage to prevent output stage degeneration for producing balanced push-pull drive signals, thereby eliminating the need for an output transformer or AC coupling.

Abstract: A feedback amplifier including a first and a second amplifier section comprises an autotransformer winding connected between common terminals of the respective amplifier sections and across a feedback circuit. A terminating impedance is connected between the output terminal of one of the amplifier sections and the autotransformer winding at a point nearer to its point of connection to the other amplifier section common terminal. Another terminating impedance is connected between the other amplifier section output terminal and the autotransformer winding at another point nearer to its point of connection to the common terminal of the above-mentioned one amplifier section. The terminating impedances may be used on the input side. They may be connected to the autotransformer winding at its points of connection to the respective common terminals, when the autotransformer may be dispensed with.