A tunable frequency selective limiter is disclosed. In one or more embodiments, the tunable frequency selective limiter includes a first electrically conductive path. The tunable frequency selective limiter also includes a ferrimagnetic layer disposed adjacent to the first electrically conductive path. The tunable frequency selective limiter further includes a second electrically conductive path coiled around the first electrically conductive path and the ferrimagnetic layer. An electromagnetic current transmitting through the second electrically conductive path produces a magnetic field coupled to the ferrimagnetic layer. The tunable frequency selective limiter further includes a dielectric layer, wherein the ferrimagnetic layer is disposed on the dielectric layer. The portions of the second electrically conductive path that are at the interface of the dielectric layer and the ferrimagnetic layer may be embedded into the dielectric layer or may be disposed on the surface of the dielectric layer.

An amplifying device includes a first amplifier, a voltage-limiting circuit, a second amplifier, a first controller, and a second controller. The first amplifier is configured to amplify an input signal. The voltage-limiting circuit is configured to limit a voltage of an output signal from the first amplifier to within a limit range. The second amplifier is configured to amplify an output signal from the voltage-limiting circuit. The first controller is configured to control the limit range in accordance with a current supplied to a load from the second amplifier. The second controller is configured to decrease an amplification factor of the first amplifier in a state in which the voltage-limiting circuit limits the voltage of the output signal from the first amplifier.

An active limiting system that is suitable to protect a low noise amplifier against the high power signals received from a signal input includes, at least one first switch, source of which is connected to a gate voltage; at least first resistor which is connected between the gate and source of the first switch; at least one second resistor, which is connected between a drain voltage and drain of the first switch; at least one second switch, source of which is connected to said drain voltage and drain of which is connected to a signal input; at least one third resistor which is connected between the drain of the first switch and gate of the second switch; at least one first filtering element, which blocks DC currents/voltages and which is connected between the source of the second switch and ground.

An active limiting system that is suitable to protect a low noise amplifier against the high power signals received from a signal input includes, at least one first switch, source of which is connected to a gate voltage; at least first resistor which is connected between the gate and source of the first switch; at least one second resistor, which is connected between a drain voltage and drain of the first switch; at least one second switch, source of which is connected to said drain voltage and drain of which is connected to a signal input; at least one third resistor which is connected between the drain of the first switch and gate of the second switch; at least one first filtering element, which blocks DC currents/voltages and which is connected between the source of the second switch and ground.

Various methods and circuital arrangements for protection of an RF amplifier are presented. According to one aspect, the RF amplifier is part of switchable RF paths that include at least one path with one or more attenuators that can be used during normal operation to define different modes of operation of the at least one path. An RF level detector monitors a level of an RF signal during operation of any one of the switchable RF paths and forces the RF signal through the at least one path with one or more attenuators while controlling the attenuators to provide an attenuation of the RF signal according to a desired level of protection at an input and/or output of the RF amplifier.

Various methods and circuital arrangements for protection of an RF amplifier are presented. According to one aspect, the RF amplifier is part of switchable RF paths that include at least one path with one or more attenuators that can be used during normal operation to define different modes of operation of the at least one path. An RF level detector monitors a level of an RF signal during operation of any one of the switchable RF paths and forces the RF signal through the at least one path with one or more attenuators while controlling the attenuators to provide an attenuation of the RF signal according to a desired level of protection at an input and/or output of the RF amplifier.

A power amplifier system having a power amplifier with a signal input and a signal output, bias circuitry coupled to the signal input, and a radio frequency (RF) peak detector having an input coupled to the signal output is disclosed. The RF peak detector is configured to generate a peak voltage signal. Temperature-compensated overvoltage protection circuitry coupled between an output of the RF peak detector and a control input of the bias circuitry is configured to respond to the peak voltage signal crossing over a predetermined peak voltage threshold and to provide an overvoltage protection control signal to cause the bias circuitry to adjust biasing for the power amplifier to reduce an overvoltage condition at the RF peak detector input.

A headset having game, chat and microphone audio signals is provided with a programmable signal processor for individually modifying the audio signals and a memory configured to store a plurality of user-selectable signal-processing parameter settings that determine the manner in which the audio signals will be altered by the signal processor. The parameter settings collectively form a preset, and one or more user-operable controls can select and activate a preset from the plurality of presets stored in memory. The parameters stored in the selected preset can be loaded into the signal processor such that the sound characteristics of the audio paths are modified in accordance with the parameter settings in the selected preset.

A headset having game, chat and microphone audio signals is provided with a programmable signal processor for individually modifying the audio signals and a memory configured to store a plurality of user-selectable signal-processing parameter settings that determine the manner in which the audio signals will be altered by the signal processor. The parameter settings collectively form a preset, and one or more user-operable controls can select and activate a preset from the plurality of presets stored in memory. The parameters stored in the selected preset can be loaded into the signal processor such that the sound characteristics of the audio paths are modified in accordance with the parameter settings in the selected preset.

A power amplifier system having a power amplifier with a signal input and a signal output, bias circuitry coupled to the signal input, and a radio frequency (RF) peak detector having an input coupled to the signal output is disclosed. The RF peak detector is configured to generate a peak voltage signal. Temperature-compensated overvoltage protection circuitry coupled between an output of the RF peak detector and a control input of the bias circuitry is configured to respond to the peak voltage signal crossing over a predetermined peak voltage threshold and to provide an overvoltage protection control signal to cause the bias circuitry to adjust biasing for the power amplifier to reduce an overvoltage condition at the RF peak detector input.