Ringtone
From Wikipedia, the free encyclopedia

A ringtone or ring tone is the sound made by a mobile phone to indicate an incoming call or text message. The term is a misnomer, as it is often used to refer to any ring sound, almost all of which are not tones. The term is most often used to refer to the customizable sounds used on mobile phones.

A phone “rings” when its network indicates an incoming call and the phone thus alerts the user. For landline telephones, the call signal can be an electric current generated by the switch to which the telephone is connected. For mobile phones, the network sends the phone a message indicating an incoming call.

A telephone “ring” is the sound generated when there is an incoming telephone call. The term originated from the fact that early telephones had a ringing mechanism consisting of a bell and an electromagnetically-driven hammer, producing a ringing sound. The aforementioned electrical signal powered the electromagnet which would rapidly move and release the hammer, striking the bell. This "magneto" bell system is still in widespread use. The ringing signal sent to a customer's telephone is AC at 90 volts and 20 hertz in North America. While the sound produced is still called a “ring”, more-recently manufactured telephones electronically produce a warbling, chirping, or other sound. Variation of the ring signal can be used to indicate characteristics of incoming calls (for example, rings with a shorter interval between them might be used to signal a call from a given number).

Piano
From Wikipedia, the free encyclopedia

The piano is a musical instrument played by means of a keyboard that produces sound by striking steel strings with felt hammers. The hammers immediately rebound allowing the strings to continue vibrating at their resonant frequency.[1] These vibrations are transmitted through a bridge to a soundboard that amplifies them.

The piano is widely used in Western music for solo performance, ensemble use, chamber music, and accompaniment. It is also very popular as an aid to composing and rehearsal. Although not portable and often expensive, the piano's versatility and ubiquity have made it one of the most familiar musical instruments. It is sometimes classified as both a percussion and a stringed instrument. According to the Hornbostel-Sachs method of music classification, it is grouped with Chordophones.

The word piano is a shortened form of the word pianoforte, which is seldom used except in formal language and derived from the original Italian name for the instrument, clavicembalo [or gravicembalo] col piano e forte (literally harpsichord with soft and loud). This refers to the instrument's responsiveness to keyboard touch, which allows the pianist to produce notes at different dynamic levels by controlling the speed with which the hammers hit the strings.

Guitar
From Wikipedia, the free encyclopedia

The guitar is a musical instrument with ancient roots that is used in a wide variety of musical styles. It typically has six strings, but four, seven, eight, ten, and twelve string guitars also exist.

Guitars are recognized as one of the primary instruments in blues, country, flamenco, rock music, and many forms of pop. They can also be a solo classical instrument. Guitars may be played acoustically, where the tone is produced by vibration of the strings and modulated by the hollow body, or they may rely on an amplifier that can electronically manipulate tone. Such electric guitars were introduced in the 20th century and continue to have a profound influence on popular culture.

Traditionally guitars have usually been constructed of combinations of various woods and strung with animal gut, or more recently, with either nylon or steel strings. Guitars are made and repaired by luthiers.

Radio
From Wikipedia, the free encyclopedia

Radio is the transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space. Information is carried by systematically changing (modulating) some property of the radiated waves, such as amplitude, frequency, or phase. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor. This can be detected and transformed into sound or other signals that carry information.

The meaning and usage of the word "radio" has developed in parallel with developments within the field and can be seen to have three distinct phases: electromagnetic waves and experimentation; wireless communication and technical development; and radio broadcasting and commercialization. Many, many individuals -- inventors, engineers, developers, businessmen -- contributed to produce the modern idea of radio and thus the origins and 'invention' are multiple and controversial.

James Clerk Maxwell, a Scottish scientist, developed the theoretical basis for explaining electromagnetism. He predicted that electric and magnetic fields can couple together to form electromagnetic waves. Heinrich Hertz, a German scientist, is credited with being the first to produce and detect such waves at radio frequencies, in 1888, using a sparkgap transmitter in the Ultra High Frequency range.

In 1893, Nikola Tesla, in America, first demonstrated the principles of wireless communications. Tesla would later ultimately hold the patent rights in the United States. Physicists and inventors such as John Stone Stone and Alexander Stepanovich Popov have cited Tesla as the originator of wireless communications. In August 1894, Oliver Lodge, an English physicist and writer, transmitted radio signals at a meeting of the British Association for the Advancement of Science at the University of Oxford. That same year, Jagadish Chandra Bose, a Bengali Indian physicist, ignited gunpowder and rang a bell at a distance using electromagnetic waves, showing independently that communication signals can be sent without using wires. In 1895, Guglielmo Marconi, an Italian inventor, began experimenting with wireless and went on to develop the world's first commercial system of radio communication. In 1896, Marconi was granted the world's first wireless telegraphy patent by the British Patent Office. Marconi has been generally credited with the development of radio by most scholars and historians. In 1909, Marconi was jointly awarded the Nobel Prize for Physics with Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy."