A method and transmitter for a Doherty power amplifier are provided. According to one aspect, a radio transmitter includes, for each carrier frequency, a filter, a main path and a peak path. The filter suppresses signals outside the selected frequency band to produce a filter output. The main path is configured to make a first adjustment of a magnitude and phase of the filter output to produce a main path signal. The peak path is configured to make a second adjustment of the magnitude and phase of the filter output to produce a peak path signal, a difference between the first adjustment and the second adjustment being dependent on the carrier frequency. Main path signals for each carrier frequency produce a composite main path signal. Peak path signals for each carrier frequency produce a composite peak path signal.

A bi-directional amplifier (BDA) comprises a first pair of amplifier transistors and a second pair of amplifier transistors, wherein the first pair of amplifier transistors are cross-coupled with the second pair of amplifier transistors, and wherein the first pair of amplifier transistors and the second pair of amplifier transistors each comprise a differential common-emitter (CE) pair (or common-source (CS) pair) with equal transistor size or different transistor size. The BDA further comprises a plurality of blocking capacitors to decouple the collector and the base biases of the first pair of amplifier transistors and the second pair of amplifier transistors. Alternatively or additionally, the BDA further comprises two input/output baluns, through which a common voltage bias is applied to the collectors of each of the differential CE pairs (or drains of CS pairs in some implementations). The baluns enable single-ended measurement and characterization.

An image sensor and electronic apparatus comprise a pixel circuit configured to generate an analog signal; a vertical signal line configured to convey the analog signal from the pixel circuit; an analog amplifier circuit configured to receive the analog signal via the vertical signal line and generate an amplified signal; and a tail current boost circuit configured to modify an instantaneous gain bandwidth product of the analog amplifier circuit by temporarily modifying a tail current of the analog amplifier circuit.

Apparatus and methods for an inverted Doherty amplifier operating at gigahertz frequencies are described. RF fractional bandwidth and signal bandwidth may be increased over a conventional Doherty amplifier configuration when impedance-matching components and an impedance inverter in an output network of the inverted Doherty amplifier are designed based on characteristics of the main and peaking amplifier and asymmetry factor of the amplifier.

Disclosed are a Doherty power amplifier (2), a controlling method and a device. In the Doherty power amplifier (2), the even order harmonic components can be fed to the drain of the amplifier to realize even order harmonic modulation. The even order harmonic components have higher power level than the odd order harmonic components, therefore, higher efficiency could be achieved.

A balancing circuit which may compensate for bandwidth attenuation introduced by interference between signals includes an amplifying circuit, a rising edge detection circuit and/or a falling edge detection circuit. By means of detecting the rising/falling edge of an original signal, the resulting pulse signal contains the phase information of a single “0” bit and a single “1” bit in the original signal, thus the phase of a rising edge or the phase of a falling edge of the original signal may be compensated respectively, so as to compensate for the high-frequency attenuation caused by interference between signals.

A pulse signal compensation circuit of a pulse generator can include a pulse measurement circuit and a compensation generator circuit. The pulse measurement circuit can be configured to receive a plurality of pulse signals and to generate an average duty cycle or pulse overlap signal proportional to the duty cycle or pulse overlap of the plurality of pulses. The compensation generator circuit can be configured to receive the average duty cycle or pulse overlap signal and generate a duty cycle or pulse overlap compensation signal based on the average duty cycle or pulse overlap signal. The compensation signal can be utilized to adjust the duty cycle, amount of positive or negative pulse width overlap, and or the like of the plurality of pulse signals.

A receiver can include a first set of one or more amplifier stages configured to amplify input signals in a plurality of communication bands. The receiver can further include a second and third set of one or more amplifier stages. The second set of one or more amplifier stages can be configured to selectively receive the input signals in the plurality of communication bands amplified by the first set of one or more amplifier stages and to amplify one or more input signals in a first one of the plurality of communication bands. Alternatively, the third set of one or more amplifier stages can be configured to selectively receive the input signals in the plurality of communication bands amplified by the first set of one or more amplifier stages and to amplify one or more input signals in a second one of the plurality of communication bands. A first set of one or more mixers can be configured to receive the input signals in the first communication band amplified by the second set of one or more amplifier stages, to receive one or more local oscillator signals for the first communication band, and to generate a baseband signal from a frequency difference of the signal of the first communication band and the one or more local oscillator signals for the first communication band. A second set of one or more mixers can be configured to receive the input signal in the second communication band amplified by the third set of one or more amplifier stages, to receive one or more local oscillator signals for the second communication band, and to generate a baseband signal of the second communication band.

A differential transimpedance amplifier includes a first pair of common-gate amplifiers having a first NMOS transistor and a second NMOS transistor configured in a cross-coupling topology using a first capacitor and a second capacitor, a second pair of common-gate amplifiers comprising a first PMOS transistor and a second PMOS transistor configured in a cross-coupling topology using a third capacitor and a fourth capacitor, wherein an output of the first pair of common-gate amplifiers and an output of the second pair of common-gate amplifiers are coupled via a fifth capacitor and a sixth capacitor.

An image sensor and processing method therein comprises a pixel circuit configured to generate a pixel signal; a vertical signal line configured to convey the pixel signal; and a charge amplifier circuit configured to receive the pixel signal, the charge amplifier circuit being switched between a low bandwidth state and a high bandwidth state in response to a control signal.