Principle: The high-frequency power amplifier is used at the final stage of the transmitter. Its function is to amplify the power of the high-frequency modulated signal to meet the transmission power requirements, and then radiate it into space through the antenna. This ensures that receivers within a certain area can receive satisfactory signal levels without interfering with adjacent channel communications.

An amplifier is a device that can amplify the voltage or power of an input signal. It is composed of electron tubes or transistors, power transformers and other electrical components. Used in various devices such as communications, broadcasting, radar, television, automatic control, etc.

A device that increases signal amplitude or power. It is an important component in signal processing in automation technology tools. The amplification function of the amplifier is achieved by controlling the energy source with the input signal, and the power consumption required for amplification is provided by the energy source. For linear amplifiers, the output is a reproduction and enhancement of the input signal. For nonlinear amplifiers, the output is a certain function of the input signal. Amplifiers are divided into mechanical amplifiers, electromechanical amplifiers, electronic amplifiers, hydraulic amplifiers and pneumatic amplifiers according to the physical quantities of the signals they process. The most widely used amplifier is the electronic amplifier. With the promotion of fluidic technology (see fluidic components), the application of hydraulic or pneumatic amplifiers has gradually increased. Electronic amplifiers are divided into vacuum tube amplifiers, transistor amplifiers, solid state amplifiers and magnetic amplifiers according to the active devices used. Among them, transistor amplifiers are the most widely used. In automated instruments, transistor amplifiers are often used for voltage amplification and current amplification of signals. The main forms are single-ended amplification and push-pull amplification. In addition, it is also commonly used for impedance matching, isolation, current-voltage conversion, charge-voltage conversion (such as charge amplifier), and the use of amplifiers to achieve a certain functional relationship between output and input (such as operational amplifiers).