Classification of Digital Public Address Amplifiers

Digital public address amplifier (DPAA) is a kind of equipment that amplifies the weak electrical signal from signal source (professional sound system is from mixer) to drive loudspeaker to make sound. Digital public address amplifier mainly includes the following categories:

1. Radio frequency power amplifier of digital public address amplifier

Radio frequency power amplifier is an important part of various wireless transmitters. In the front stage circuit of the transmitter, the radio frequency signal power generated by the modulation oscillation circuit is very small, which needs to go through a series of amplification - buffer stage, intermediate amplifier stage and final stage power amplifier stage. After obtaining enough radio frequency power, it can be fed to the antenna for radiation. In order to obtain enough radio frequency output power, radio frequency power amplifier must be used.

The radio frequency power amplifier is an important part of transmitting equipment. The main technical specifications of radio frequency power amplifier are output power and efficiency. In addition, the harmonic component in the output should be as small as possible to avoid interference with other channels.

2. High frequency power amplifier of digital public address amplifier

High frequency power amplifier, as another kind of digital public address amplifier is used in the final stage of the transmitting stage. Its function is to amplify the high-frequency modulated signal to meet the requirements of transmission power, and then radiate it to space through the antenna to ensure that the receiving stage in a certain area can receive satisfactory signal level, and does not interfere with the communication of adjacent channels.

High frequency power amplifier is an important component of transmitter in communication system. According to the working frequency band, it can be divided into two kinds: narrow band high frequency power amplifier and wide band high frequency power amplifier. The narrow band high frequency power amplifier usually takes the frequency selection circuit with the function of frequency selection filtering as the output circuit, so it is also called the tuned power amplifier or resonant power amplifier. The output circuit of the wide high frequency power amplifier is the transmission line transformer or other wide band matching circuit. Therefore, it is also called non-tuned power amplifier. High frequency power amplifier is a kind of energy converter, which converts the direct currency energy supplied by power supply into high frequency alternating current output.