Amplitude modulation is a technique used to transmit content on a radio carrier wave. Changes, or modulations, in the transmitted signal's strength help to specify the sound or image to be reproduced on the receiving end of the signal. Amplitude modulation was first used in the early 1900s and has been in constant use since the early days of radio.Continue Reading
Amplitude modulation is used for broadcasting radio transmissions, ground-to-air communication, two-way radio, short-range wireless transmission, Wi-Fi and cellular telecommunications. The abbreviation "AM" is usually used to refer to radio transmissions on the medium-wave broadcast band. Although amplitude modulation is usually thought of in terms of radio, the technique can also carry video signals.
Amplitude modulation is the simplest way of modulating an electronic communications signal, and the demodulation of the signal, which converts it back into an audio frequency signal, is simple as well. An AM signal has two-thirds of its power concentrated in the carrier signal, which carries no useful information, and the rest in two mirror-image sidebands; as a result, the power usage of AM is inefficient. It also uses bandwidth inefficiently and is prone to high levels of noise because an AM receiver detects electromagnetic interference in proportions equal to its detection of the actual signal sent.Learn more about Optics & Waves
Pulse position modulation, or PPM, is a signal modulation used for digital and analog transmissions. PPM is used mostly for optical communication systems such as fiber optic and infrared remotes, when efficiency is needed and there is little chance of interference.Full Answer >
Differential pulse code modulation is a technique of analog to digital signal conversion. This technique samples the analog signal and then quantizes the difference between the sampled value and its predicted value. It then encodes the signal to form a digital value.Full Answer >
Frequency Shift Keying, or FSK, is a modulation technique that transmits digital signals over telephone lines, cables, optical fiber or wireless media. FSK data consist of two binary states, 0 and 1, represented by two different waves known as "space" to represent the 0s and "mark" to represent the 1s.Full Answer >
Amplitude is the factor by which a function is stretched vertically. The period of a repeating graph is the width of each repeat. The phase shift is the amount that the graph is moved horizontally.Full Answer >