In a system, apparatus and method for achieving scanning safety for a magnetic resonance conditionally safe implant, an FPO processor converts an RF power signal received from an RF power sensor of an MR scanner into an RF power parameter, and converts a gradient power signal received from an MR gradient power sensor of the MR scanner into a gradient power parameter. Upon detecting that the RF power parameter exceeds an RF power limit value or/and the gradient power parameter exceeds a gradient power limit value, the FPO processor sends a shutdown signal, to shut down an RF power amplifier or/and a gradient power amplifier in the MR scanner. The MR scanner is thereby enabled to realize the FPO mode, without altering MR scanner software, and the workload is small and easy to carry out.

An industrial control I/O module for interfacing with industrial control equipment, such as sensors and actuators, can be configured to dynamically provide differing resistances in each channel as may be required for reliably achieving particular modes of operation in the channel. Providing differing resistances in such channels flexibly allows different modes in the channel to provide universal I/O capability. Modes of operation could include, for example, digital output, digital input, analog output, analog input and the like, in the same channel, but at different times. In one aspect, a processor or voltage divider can be used to control an amplifier, with feedback, driving a transistor in a channel to dynamically adjust resistance in the channel by selectively biasing the transistor to achieve a resistance in the channel suitable for the selected mode.

A method for digital predistortion (DPD) calibration in a wireless communication device is provided that includes transmitting, by transmission circuitry of the wireless communication device, a plurality of pulses, where each pulse corresponds to an amplitude step in a pattern of amplitude steps, where the amplitude steps are separated by silence gaps, receiving each pulse in receiver circuitry of the wireless communication device, generating, by an accumulator component of the wireless communication device, an accumulated sample for each pulse based on a plurality of samples output by the receiver circuitry for the pulse, and computing, by a processor of the wireless communication device, amplitude dependent gain (AM/AM) and amplitude dependent phase shift (AM/PM) values for each accumulated sample.

An amplifier arrangement (200) for amplifying input signals and a method for operating the amplifier arrangement are disclosed. The amplifier arrangement (200) comprises a main amplifier circuit (210) having an input and an output; a first (221) and second (222) auxiliary amplifier circuits each having an input and an output, wherein each of the first (221) and second (222) auxiliary amplifier circuits being selectively operable to operate in combination with the main amplifier circuit (210). The amplifier arrangement (200) further comprises a single hybrid coupler circuit (230) having a first port (221) being coupled to the output of the main amplifier circuit (210), a second port (232) being coupled to the output of the first auxiliary amplifier circuit (221), a third port (233) being coupled to the output of the second auxiliary amplifier circuit (222) and a fourth port (234) being coupled to the load (240) of the amplifier (200).

A multi-channel switchmode audio amplifier is configured by a programmed processor such that each channel drives separate loads, is connected in parallel or is configured in a bridge-tied mode as well as combinations thereof. In one embodiment, amplifier channels that are connected in parallel have power amplifiers that are driven with signals from a single modulator. A feedback circuit and error amplifier from one channel controls the modulated signal that is applied to each parallely connected amplifier channel. Current feedback circuits for parallely connected amplifier channels are eliminated by tightly controlling the timing of switching in the power amplifier output stages.

An integrated circuit may have two signal paths: an open-loop modulator (which may comprise a digital-input Class-D amplifier) and a closed-loop modulator (which may comprise an analog-input Class-D amplifier). A control subsystem may be capable of selecting either of the open-loop modulator or the closed-loop modulator as a selected path based on one or more characteristics (e.g., signal magnitude) of an input audio signal. For example, for higher-magnitude signals, the closed-loop modulator may be selected while the open-loop modulator may be selected for lower-magnitude signals. In some instances, when the open-loop modulator is selected as the selected path, the closed-loop modulator may power off, which may reduce power consumption. In addition, one or more techniques may be applied to reduce or eliminate user-perceptible audio artifacts caused by switching between the open-loop modulator and the closed-loop modulator, and vice versa.

The disclosure presents a method and an amplifier system for minimizing variation in an acoustical signal caused by variation in gain of an amplifier, comprising a battery for providing a supply voltage to the amplifier, a digital signal processor for providing the acoustical signal to the amplifier, a controller unit receiving an enablement signal when the supply voltage is in an offset mode, and based on the enablement signal requesting a measured voltage during a time period, and a first analog-to-digital converter configured for measuring the supply voltage to the amplifier when receiving the request from the controller unit or the first analog-to-digital converter is configured for measuring the supply voltage to the amplifier continuously, and where variations in the measured voltage relates to variations in the supply voltage during the time period. Furthermore, the controller unit is configured to predict offset modes (i.e. changes) in the supply voltage based on the enablement signals and a fitting of the measured voltages, and wherein the controller unit is configured to generate a compensating signal based on the fitting and transmit the compensating signal to the digital signal processor, the digital signal processor is then configured to minimize variation in the acoustical signal at the output of the amplifier by compensating the variation in gain of the amplifier based on the compensating signal.

An audio signal control circuit includes an impedance calculator, a suppression value setter, a level detector, and a level controller. The impedance calculator is configured to calculate impedance of a speaker from voltage and current of an audio signal to be outputted to the speaker. The suppression value setter is configured to set a suppression value of the audio signal, using the impedance. The level detector is configured to perform level detection using: i) the voltage when the impedance is equal to or more than a switching threshold value, and ii) the current when the impedance is less than the switching threshold value. The level controller is configured to perform level control of the audio signal using: i) a level of a detection signal that has been detected by the level detector, and ii) the suppression value.

System and method for efficient operation of power amplifiers in dynamic carrier systems. In one example, the method includes determining a composite RMS power and peak power for a carrier configuration of an RF transmitter, determining a number of active banks of power amplifiers as a function of composite RMS power and peak power, and determining a number of active power amplifiers within a bank of power amplifiers as a function of composite RMS power and peak power. The method also includes activating a first bank of power amplifiers and/or a second bank of power amplifiers based on the determined number of active banks of power amplifiers and activating a subset of a one or more first power amplifiers of the first bank of power amplifiers and a one or more second power amplifiers of the second bank of power amplifiers based on the determined number of active power amplifiers.

An industrial control I/O module for interfacing with industrial control equipment, such as sensors and actuators, can be configured to dynamically provide differing resistances in each channel as may be required for reliably achieving particular modes of operation in the channel. Providing differing resistances in such channels flexibly allows different modes in the channel to provide universal I/O capability. Modes of operation could include, for example, digital output, digital input, analog output, analog input and the like, in the same channel, but at different times. In one aspect, a processor or voltage divider can be used to control an amplifier, with feedback, driving a transistor in a channel to dynamically adjust resistance in the channel by selectively biasing the transistor to achieve a resistance in the channel suitable for the selected mode.