A capacitive trans-impedance amplifier comprising a voltage amplifier having an inverting input terminal for connection to an input current source. A feed-back capacitor is coupled between the inverting input terminal and the output terminal to accumulate charges received from the input current source and to generate a feed-back voltage accordingly. A calibration unit includes a calibration capacitor electrically coupled, via a calibration switch, to the inverting input terminal and electrically coupled to the feed-back capacitor. The calibration unit is operable to switch the calibration switch to a calibration state permitting a discharge of a quantity of charge from the calibration capacitor to the feed-back capacitor. The capacitive trans-impedance amplifier is arranged to determine a voltage generated across the feed-back capacitor while the calibration switch is in the calibration state and to determine a capacitance value (C=Q/V) for the feed-back capacitor according to the value of the generated voltage (V) and the quantity of charge (Q).

Provided is a sensor interface including a first cantilever beam bundle including at least one resonator and a first output terminal, a second cantilever beam bundle including at least one resonator and a second output terminal, and a differential amplifier including a first input terminal electrically connected to the first output terminal of the first cantilever beam bundle and a second input terminal electrically connected to the second output terminal of the second cantilever beam bundle.

A power amplifier circuit includes a power amplification circuit and a diode assembly. The diode assembly is connected in series with a transistor amplification circuit of the power amplification circuit, and the transistor amplification circuit is configured to, when load of power amplifier is mismatched, turn the diode assembly on, so as to divide current voltage to at least two electrodes of the transistor amplification circuit.

An amplifier comprising a gain stage with a feedback network comprising two ports between which at least three capacitors are connected in series and between each pair of capacitors a resistor is connected to a predetermined voltage. The gain stage is provided in a feedback loop over a primary amplifier.

An amplifier includes an input circuit, an amplification circuit, and at least two feedback circuits. The input circuit is connected with an input end of the amplification circuit; an output end of the amplification circuit is connected with a first end of each of the feedback circuits respectively; a second end of each of the feedback circuits is connected with the input circuit respectively. The input circuit is configured to receive an input signal and a feedback signal; the amplification circuit is configured to amplify the input signal and the feedback signal to obtain an amplified signal. The feedback signal is fed back to the input circuit by feeding back at least a part of the amplified signal through a target feedback circuit; and the target feedback circuit is a feedback circuit that depends on the type of the input signal of the at least two feedback circuits.

According to one aspect, embodiments of the invention provide a distortion detection circuit comprising an input configured to be coupled to an output stage of an amplifier and to receive an RF signal from the output stage of the amplifier, an output configured to be coupled to a module of the amplifier, at least one peak detection circuit coupled to the input and configured to monitor the RF signal and output a first signal based on positive voltage peaks of the RF signal, and a differential amplifier having an input coupled to the at least one peak detection circuit and configured to monitor the first signal and provide a second signal to the output in response to a voltage of the first signal exceeding a threshold level indicative of distortion in the RF signal.

An amplifier assembly (100) includes an amplifier (102) having an input terminal, an output terminal and a feedback terminal; a first feedback path connecting the output terminal to the feedback terminal; a second feedback path connecting the output terminal to the feedback terminal; a switch (124) positioned in the second feedback path, the switch (124) opening or closing in response to a voltage at the output terminal relative to a breakpoint, when the switch (124) is open, the amplifier assembly (100) has a first gain and when the switch (124) is closed, the amplifier assembly (100) has a second gain; and a thermally variable element (152) connected to the switch (124), the thermally variable element (152) configured to generate a compensation voltage to maintain the breakpoint in response to varying temperature of the switch (152).

An automatic gain control (AGC) transimpedance amplifier (TIA) uses a differential structure with feedback PIN diodes to adjust the loop gain of the amplifier automatically to maintain stability over a wide dynamic range when converting optical power using a photodiode to an electrical signal. A stable DC current derived from the photodiode current sets the voltage gain of the amplifier. The use of ultra-linear long carrier lifetime PIN diodes assures the transimpedance feedback resistance is linear. The AGC function adjusts the gain of the TIA to provide a linear stable differential transresistance controlled by the photodiode current; a linear stable AGC function using current supplied by the photodiode; an improvement of about 10 db of the transresistance dynamic range; and reduces the need for internal and external circuitry needed to provide the same function. The TIA is applicable to CATV optical systems which have very strict linearity requirements.

A method for improving the linearity of a radio frequency power amplifier, a compensation circuit (307) for implementing the method, and a communications terminal with the compensation circuit (307). In the method, a compensation circuit (307) is connected between a base (a3) and a collector (b3) of a transistor of a common emitter amplifier (306), in order to neutralize the impact of a variation in capacitance between the base (a3) and the collector (b3) of the transistor (306) according to a radio frequency signal. No additional direct-current power consumption is needed, and degradation in performance of other radio frequency power amplifiers can be avoided. The corresponding compensation circuit (307) can be easily integrated with a main amplification circuit, without affecting other performance of the main amplification circuit, and provides high adjustability.

An amplifier comprising a gain stage with a feedback network comprising two ports between which at least three capacitors are connected in series and between each pair of capacitors a resistor is connected to a predetermined voltage. The gain stage is provided in a feedback loop over a primary amplifier.