Ghana

Coordinates: 8°N 2°W / 8°N 2°W / 8; -2

Ghana (ⁱ/ˈɡɑːnə/), officially called the Republic of Ghana, is a sovereign unitary presidential constitutional democracy, located along the Gulf of Guinea and Atlantic Ocean, in the subregion of West Africa. Spanning a land mass of 238,535 km², Ghana is bordered by the Ivory Coast in the west, Burkina Faso in the north, Togo in the east and the Gulf of Guinea and Atlantic Ocean in the south. The word Ghana means "Warrior King" in Mande.

The territory of present-day Ghana has been inhabited for millennia, with the first permanent state dating back to the 11th century. Numerous kingdoms and empires emerged over the centuries, of which the most powerful was the Kingdom of Ashanti. Beginning in the 15th century, numerous European powers contested the area for trading rights, with the British ultimately establishing control of the coast by the late 19th century. Following over a century of native resistance, Ghana's current borders were established by the 1900s as the British Gold Coast. In 1957, it became the first sub-saharan African nation to declare independence from European colonisation.

Radio

Radio is the use of radio waves is to carry information, such as sound, by systematically modulating some property of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.

Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and vice versa. An antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected. The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.

Radio broadcasting

Radio broadcasting is a unidirectional wireless transmission over radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both. Audio broadcasting also can be done via cable radio, local wire television networks, satellite radio, and internet radio via streaming media on the Internet. The signal types can be either analog audio or digital audio.

In 2009, there were 3,494 radio broadcasting stations in the United States.

History

The earliest radio stations were simply radiotelegraphy systems and did not carry audio. For audio broadcasts to be possible electronic detection and amplification devices had to be incorporated.

The thermionic valve was invented in 1904 by the English physicist John Ambrose Fleming. He developed a device he called an "oscillation valve" (because it passes current in only one direction). The heated filament, or cathode, was capable of thermionic emission of electrons that would flow to the plate (or anode) when it was at a higher voltage. Electrons, however, could not pass in the reverse direction because the plate was not heated and thus not capable of thermionic emission of electrons. Later known as the Fleming valve, it could be used as a rectifier of alternating current and as a radio wave detector. This greatly improved the crystal set which rectified the radio signal using an early solid-state diode based on a crystal and a so-called cat's whisker. However, what was still required was an amplifier.

Radio astronomy

Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang theory, was made through radio astronomy.

Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used singularly, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis. The use of interferometry allows radio astronomy to achieve high angular resolution, as the resolving power of an interferometer is set by the distance between its components, rather than the size of its components.

FM & AM

FM & AM is the third album by American comedian George Carlin. This album was originally released in 1972 on the Atlantic Records subsidiary label Little David Records, later reissued on Carlin's Eardrum Records label. It was also included as part of the 1992 Classic Gold collection, and The Little David Years (1971-1977) box set.

The album incorporates (and mocks) the old clean cut he performed on the Ed Sullivan Show on its "AM" side (in monaural), while featuring the counterculture material he was becoming known for on its "FM" side (in stereo with Carlin on the left channel and the audience on the right). Carlin's official website refers to the album as a sort of comedy concept album and says that it "marked Carlin's metamorphosis from straight-laced to hippie, intentionally embracing the growing counterculture."

FM & AM won the 1972 Grammy Award for Best Comedy Album.

Track listing

Side one (FM)