4 results about "Feedforward amplifiers" patented technology

Provided are feedforward amplifier circuit, audio amplifier and audio playing device, including: a main amplifier circuit, an adder circuit, a sub-amplifier circuit and a subtractor circuit, wherein the main amplifier circuit adds distortion to a first input signal to output a distorted signal, and inputs the distorted signal to the adder circuit and the subtractor circuit for performing feedforward correction; the sub-amplifier circuit amplifies a second input signal and serves as a positive input of the subtractor, so that a signal gain output by the subtractor is equal to a signal gain of the main amplifier; the subtractor circuit, with the distorted signal as a negative input, reversely amplifies the distorted signal and afterwards performs feedforward; and the adder circuit superimposes the distorted signal output by the main amplifier circuit and the reversely amplified distorted signal output by the subtractor, so as to output a distortion-free signal.

A feedforward circuitry system for regulating voltage includes a voltage regulator for generating a regulated voltage, a bias generator operatively connected to the voltage regulator for generating a sub-threshold gate bias, a plurality of coupling capacitors, at least one of the coupling capacitors operatively connected to the bias generator for reading the sub-threshold gate bias and a feedforward amplifier operatively coupled with at least one of the coupling capacitors, characterized in that the plurality of coupling capacitors being configured to direct AC-couple an output transition of CMOS logic gates. A method for regulating voltage in a feedforward circuitry system through a direct AC-coupling is also provided.

Tuning of carrier and intermodulation cancellation loops of a feed-forward amplifier at a radio transmitter occurs. For the CC loop, in an absence of carriers, a preheating process comprises enabling: a main power amplifier of the CC loop and tone(s) operatively coupled to an input of the feed-forward amplifier; tuning the CC loop using the tone(s) occurs to determine tone CC loop tuning parameters, which, when a carrier is about to be keyed at the radio transmitter are used to determine carrier CC loop offsets that are applied to the CC loop. For IMDC loop tuning, the preheating process is modified to enable an error power amplifier of the IMDC loop and tone(s) within the main power amplifier path to determine tone IMDC loop tuning parameters which, when a carrier is about to be keyed are used to determine carrier IMDC loop offsets that are applied to the IMDC loop.

The invention provides a feed-forward circuitry (1) for regulating a voltage, comprising: a voltage regulator (12) for generating a regulated voltage; a bias generator (14) operably connected to the voltage regulator (12) for generating a sub-threshold gate bias; a plurality of coupling capacitors (16), at least one of the plurality of coupling capacitors (16) being operably connected to the bias generator; and a feed-forward amplifier (18) operably coupled with at least one of the plurality of coupling capacitors, characterized in that the plurality of coupling capacitors (16) are configured to be AC coupled with an output of the CMOS logic gate. The invention also discloses a method for regulating the voltage in the feed-forward circuitry (1) by AC coupling.