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The ZN414 is a low cost, single-chip AM radio integrated circuit. Launched in 1972, the part was designed and supplied by Ferranti , but was second sourced from GEC-Plessey . The ZN414 was popular amongst hobbyists, as a fully working AM radio could be made with just a few external components, a crystal earpiece and a 1.5 V cel l.
The term radio receiver is understood in this article to mean any device which is intended to receive a radio signal in order to generate useful information from the signal, most notably a recreation of the so-called baseband signal (such as audio) which modulated the radio signal at the time of transmission in a communications or broadcast system.
Note that higher voltage is required if the LM386 is to be used. Therefore, small signal diodes (such as 1N4148 ) are recommended to create a voltage drop , or use a Zener DC–DC converter with a red LED (in forward, can double as a power indicator) and a resistor (several hundred ohms for 9V operation), to avoid overvolting the MK484.
A radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. Radio waves are electromagnetic waves with frequencies between about 30 Hz and 300 GHz. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the ...
Basic automatic frequency control in a radio receiver. У = RF amplifier stages, Д = frequency discriminator stage. In radio equipment, Automatic Frequency Control (AFC), also called Automatic Fine Tuning (AFT), is a method or circuit to automatically keep a resonant circuit tuned to the frequency of an incoming radio signal.
The following outline is provided as an overview of and topical guide to radio: Radio – transmission of signals by modulation of electromagnetic waves with frequencies below those of visible light . [ 1 ]
Circuit symbol of a heptode. The development of the pentagrid or heptode (seven-electrode) valve was a novel development in the mixer story. The idea was to produce a single valve that not only mixed the oscillator signal and the received signal and produced its own oscillator signal at the same time but, importantly, did the mixing and the oscillating in different parts of the same valve.
A simple crystal radio with no tuned circuit can be used to listen to strong AM broadcast signals. An early form of envelope detector was the crystal detector, which was used in the crystal set radio receiver. A later version using a crystal diode is still used in crystal radio sets today.