Radio Tuner Receivers

Generally, in electronics, radio and radio receiver are often used to describe those receivers designed for the sound signals transmitted by radio broadcasting services.  This was historically the first mass-market radio application.

A radio receiver is defined as an electronic circuit that receives its input from antenna, using electronic filters and to separate a wanted radio signal from all other signals that are picked up.  It amplifies it to a level suitable for further processing, and finally converts through the use of demodulation and decoding the signal into a form usable for the consumer, such as sound, pictures, digital data, measurement values and navigational positions.

The radio receiver, known as the thunderstorm register was designed by Alexander Stepanovich Popov, and shown for the first time at the All-Russia exhibition in 1896. He was the first to demonstrate the practical application of electromagnetic radio waves, although he did not care to apply for a patent for his invention.

A device called a coherer became the basis for receiving radio signals. The first person to use the device to detect radio waves was a Frenchman named Edouard Branly.  It was made popular by Oliver Lodge when he gave a lecture in 1898 in honour of Hertz. Lodge also made improvements to the coherer. Guglielmo Marconi believed that these new waves could be used to communicate over great distances and made significant improvements to both radio receiving and transmitting apparatus. In 1895 Marconi demonstrated the first viable radio system, leading to transatlantic radio communication in December 1901.

John Ambrose Fleming’s development of an early thermionic valve to help detect radio waves was based upon a discovery of Thomas Edison’s (called “The Edison Effect”, which essentially modified an early light bulb). Fleming called it his "oscillation valve" because it acted in the same way as water valve in only allowing flow in one direction. While Fleming's valve was a great stride forward it would take some years before thermionic, or vacuum tube technology was fully adopted.

There are hundreds of types of radio receivers including those that are listed on:

    * Consumer audio and high fidelity audio receivers and AV receivers used by home stereo listeners and audio and home theatre systems enthusiasts.
    * Communications receivers, used as a component of a radio communication link, which is characterized by high stability and reliability of performance.
    * Simple crystal radio receivers (also known as a crystal set) which operate using the power received from radio waves.
    * Satellite television receivers, used to receive television program from communication satellites in orbit.
    * Specialized-use receivers such as telemetry receivers that allow the remote measurement and reporting of information.
    * Measurement receivers which are calibrated laboratory-grade devices that are used to measure the signal strength of broadcasting stations, the electromagnetic interference radiation emitted by electrical products, as well as to calibrate RF attenuators and signal generators.
    * Scanners are specialized receivers that can automatically scan two or more discrete frequencies, stopping when they find a signal on one of them and then continuing to scan other frequencies when the initial transmission ceases. They are mainly used for monitoring VHF and UHF radio systems.