Abstract :
This paper will concentrate on radio communications receivers. These are normally intended for professional use in maritime, aeronautical and signal monitoring services, principally in the range 10 kHz to 30 MHz. However, they are also used by radio amateurs in conjunction with a separate transmitter and by radio hobbyists for general listening. In 1965 the communications receiver was still basically an improved version of that produced twenty five years earlier. Since 1965 it has evolved into electronic equipment capable of remote or automatic operation. In recent years, digital signal processing has been a key area of development and will, no doubt, remain so for the foreseeable future
