An automatic gain control (AGC) circuit and method are provided herein to control the gain, and the gain step size, of an amplifier circuit based on a duration of a detected overload condition. According to one embodiment, a method of gain control may include comparing a received signal to a threshold value, detecting an overload condition if the received signal exceeds the threshold value, detecting a duration of the overload condition, and controlling the gain, and the gain step size, of the amplifier circuit based on the detected duration of the overload condition.

An automatic gain control (AGC) circuit and method are provided herein to control the gain, and the gain step size, of an amplifier circuit based on a duration of a detected overload condition. According to one embodiment, a method of gain control may include comparing a received signal to a threshold value, detecting an overload condition if the received signal exceeds the threshold value, detecting a duration of the overload condition, and controlling the gain, and the gain step size, of the amplifier circuit based on the detected duration of the overload condition.

An optimised method for driving a loudspeaker is used for protecting the loudspeaker from damage due to excessive excursion or from overheating. The playback power of an incoming audio data stream is compared with a feedback power derived from the loudspeaker actuator and the comparison is used to adjust the frequency response of the loudspeaker, across individual sub bands.

A transmission module includes n oscillator modules and a phase command signal generator. Each of the oscillator modules includes a voltage controlled oscillator and an amplification circuit. The voltage controlled oscillators output transmission high-frequency signals having the same frequency and synchronized among the n oscillator modules by synchronous control based on a common reference signal. The amplification circuits each perform power amplification for the transmission high-frequency signal from a corresponding one of the voltage controlled oscillators and output the resultant signal. Phases of the transmission high-frequency signals synchronized among the n oscillator modules and output from the voltage controlled oscillators are separately controlled according to respective n phase command signals from the phase command signal generator.

A circuit comprising: an input terminal; a first amplifier coupled to the input terminal of the circuit to receive an input signal; a first inductor having a first terminal coupled to the input terminal and a second terminal configured to be coupled to the ground terminal, wherein the first inductor is arranged with a second inductor and configured to magnetically couple therewith, wherein said second inductor is coupled to the first amplifier and is configured to sense a current through the amplifier.

The apparatus includes a first transistor having a gate/base terminal to receive a first drive control signal used for controlling a driver stage of the transceiver and a drain/collector terminal coupled to a control terminal of a switch of the transceiver. The first transistor is switched on when the first drive control signal is at a first level that enables the driver stage to amplify a first RF signal. When the first transistor is switched on, the drain/collector terminal of the first transistor outputs to a control terminal of the switch a switch control signal at a second level that enables the switch to provide a portion of the RF signal reflected by the antenna to the load.

Disclosed is a radio frequency unit, including a power amplification module, a filtering module and a signal connector; where one end of the signal connector is connected to the filtering module, and the other end is connected to the power amplification module; the power amplification module is provided with a power amplification connector; a guide structure for guiding the power amplification connector to be coaxially aligned with the signal connector is formed on one end of the signal connector connected with the power amplification module; and through the guide structure, the power amplification connector is coaxially connected with the signal connector.

Disclosed are embodiments of portable antennae and systems for radio communications requiring low-noise receiving means, or in which interconnecting transmission line insertion loss between receiver or transceiver equipment and a distant antenna impairs such radio communications. A method of use is also disclosed, in which an antenna in a passive state may be turned on automatically upon the initiation by a radio operator of a transmission.

Systems and methods are provided for improved stability of driver amplifiers. In one example, a system includes an NMOSFET power device operable to generate a current signal at a drain terminal. The system further includes a current comparison amplifier operable to amplify a difference signal comprising a difference between a replica current signal of the NMOSFET power device and a reference current signal to drive a current comparison amplifier voltage output signal. The system further includes a PMOSFET clamp device comprising a source terminal coupled to a gate terminal of the NMOSFET power device operable to limit a voltage at the gate terminal of the NMOSFET power device responsive to the current comparison amplifier voltage output signal.

A protection and attenuation circuit for sensitive AC loads is described. The circuit provides AC power protection and attenuation utilizing high-efficiency switch-mode techniques to attenuate an AC power signal by incorporating a bidirectional, transistorized switch driven from a pulse width modulation signal, PWM. The circuit monitors characteristics of the AC power signal driving a known load and characteristics of the load or other elements and determines the duty cycle of the pulse width modulated signal, PWM, based upon the duration and amplitude of the over-voltage, over-current, over-limit or other event.