An attenuation circuit comprising: a connection-node for connecting to an RF connection; an isolation-capacitor connected in series between the connection-node and an internal-node; a first-bias-resistor connected in series between a first-control-node and the internal-node; a second-bias-resistor connected in series between the internal-node and a second-control-node; a first-attenuation-diode connected in series between the first-control-node and the internal-node, wherein the anode of the first-attenuation-diode is closest to the first-control-node; a second-attenuation-diode connected in series between the internal-node and the second-control-node, wherein the anode of the second-attenuation-diode is closest to the internal-node; a first-decoupling-capacitor connected in series between the first-control-node and the reference-node; and a second-decoupling-capacitor connected in series between the second-control-node and the reference-node.

A close-down pop reduction system and a method for close-down pop reduction in an audio amplifier assembly are disclosed. The switching power conversion system comprises a forward path having a compensator and a switching power stage and a signal path from an output of a comparator in the switching power stage to a sequence control unit. The signal path includes a close-down timing circuit configured to provide a timing signal. The sequence control unit is configured to eliminate the input signal, increase the switch frequency of the close-down pop reduction system and disable the switching power stage at a moment in time within a PWM pulse of the switching power stage. Hereby, it is e.g. possible to minimize the audible pop during close-down of audio amplifier assemblies.

Example embodiments provide a process that includes one or more of receiving an audio signal at a feedback compressor circuit, multiplying the received audio signal with a power feedback signal to create a product audio signal, wherein the feedback signal comprises a low-pass filtered signal, applying a power amplifier to the product audio signal, and providing the amplified product audio signal as an output signal to a speaker.

The embodiments described herein include amplifiers configured for use in radio frequency (RF) applications. In accordance with these embodiments, the amplifiers are implemented to generate a shaped envelope signal, and to apply the shaped envelope signal to transistor gate(s) of the amplifier to provide gate bias modulation. So configured, the shaped envelope signal may facilitate high linearity in the amplifier.

An apparatus and a method for improving nonlinearity of a power amplifier in a wireless communication system are provided. A transmission apparatus in a wireless communication system comprises: at least one processor; a transceiver; and an amplifier for amplifying a signal provided from the transceiver, wherein if a power of a signal inputted into the transceiver is smaller than a reference value, the transceiver attenuates the power of the signal based on a gain compensation value corresponding to the power of the signal.

Extracting a common signal from multiple audio signals may include summing a first signal and a second signal to obtain a first+second signal; subtracting the second signal from the first signal to obtain a first−second signal; transforming the first+second signal and the first−second signal to frequency domain representations; calculating absolute value of the frequency domain representations of the first+second signal and the first−second signal; subtracting the absolute value of the frequency domain representation of the first−second signal from the absolute value of the frequency domain representation of the first+second signal to obtain a difference signal; multiplying the difference signal by the frequency domain representation of the first+second signal to obtain a product signal; dividing the product signal by the absolute value of the frequency domain representation of the first+second signal to obtain a frequency domain representation of the common signal; and transforming the frequency domain representation to the common signal.

A circuit arrangement for compensating for an attenuation occurring in an antenna signal link between a mobile radio terminal and an antenna has at least one antenna signal amplifier in the antenna signal link and a control unit for adjusting a gain factor. The antenna signal conducted through an associated antenna signal amplifier is amplified or attenuated. The circuit arrangement has a detection unit for detecting an antenna signal power (P.sub.M, P.sub.A) of the antenna signal in the signal path of the antenna signal link. The control unit is configured for changing the gain factor, detecting a change, changing the transmit power (P.sub.M) of the mobile radio terminal, and adapting the gain factor to the coupling attenuation of the antenna signal link in dependence on a detected response of the mobile radio terminal.

Example embodiments provide a process that includes one or more of receiving an audio signal at a feedback compressor circuit, determining how much to attenuate the audio signal when a power level of the audio signal exceeds a threshold power level, combining the audio signal with an auxiliary attenuation signal from an auxiliary attenuation source and a compressed attenuation signal from the feedback compressor circuit to create a combination signal, and generating an audio output signal of the feedback compressor circuit based on the combination signal.

Power amplifier having analog pre-distortion by adaptive degenerative feedback. In some embodiments, a pre-distortion circuit for an amplifier can include a transistor having an input node for receiving an input signal, an output node for providing an output signal having a gain relative to the input signal, and a common node for coupling to a ground. The pre-distortion circuit can further include a degeneration circuit implemented between the common node and the ground, with the degeneration circuit being configured to introduce a feedback response that reduces the gain when the input signal has a power level at or below a selected level. The degeneration circuit can be further configured to be disabled or provide a reduced feedback response when the input signal has a power level that exceeds the selected level.

A number of biasing circuits for amplifiers including voltage controlled amplifier is presented. Also a number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.