Chapter 1Introduction

1.1 Radio Transmitters

Radio communication utilizes radio waves as a transmission and receiving medium. A radio transmitter consists of information source producing modulating signal, modulator, radio-frequency (RF) power amplifier, and antenna. A power amplifier is a circuit that increases the power level of a signal by using energy taken from a power supply [1–28]. Both the efficiency and distortion are critical parameters of power amplifiers. A radio receiver consists of an antenna, front end, demodulator, and audio amplifier. A transmitter and receiver combined into one electronic device is called a transceiver. A radio transmitter produces a strong RF current, which flows through an antenna. In turn, a transmitter antenna radiates electromagnetic waves (EMWs), called radio waves. Transmitters are used for communication of information over a distance, such as radio and television broadcasting, mobile phones, wireless computer networks, radio navigation, radio location, air traffic control, radars, ship communication, radio-frequency identifications (RFIDs), collision avoidance, speed measurement, weather forecasting, and so on. The information signal is the modulating signal, and it is usually in the form of audio signal from a microphone, video signal from a camera, or digital signal. Modern wireless communication systems include both amplitude-modulated (AM) and phase-modulated (PM) signals with a large peak-to-average ratio (PAR). Typically, the ...

Get RF Power Amplifier, 2nd Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.