Channel
(1-general) A channel is a stream of information transmitted as part of a distinct communication, or conversation, or for a particular purpose or end use. One channel may be distinguished from other channels by the time of occurrence of the transmission, by the format or organization of its content, by the frequency of a carrier signal used to transmit it, or by some secondary property such as the type of error detecting code used for it, or by other properties. Due to the advance of technology, a single channel may at some time historically be modified so that it carries multiple channels. For example, when the only distinguishing feature of two radio signals is their carrier frequency and each one carries only one conversation, each one is described as a channel. Different carrier frequencies are designated by distinct channel numbers. At a later date, time division multiplexing is used with radio signals to distinguish 3 or 8 distinct conversations on one modulated radio carrier frequency. Confusion can arise because the 3 or 8 distinct conversations, each using a designated time slot in time division multiplexing, are described as separate channels. At the same time, the entire signal (comprising 3 or 8 channels) is also described by some as a channel. In some cases the reader must read carefully, with awareness of the changing historical meanings of some terms. Regarding this particular example, the entire conglomeration of 3 or 8 time slots is described best as a "modulated carrier" and not as a channel. (2-broadcasting) A channel is a portion of the radio frequency spectrum assigned to a particular broadcasting station. (3- signal path) A channel is a transmission path between two or more termination points. The term channel can refer to a 1-way or 2-way path. (4-video effects) A channel is a digital effects processing path for video. (5-programming) Channels are collections of content that can be associated with a brand or media access point. (5-advertising) A channel is the system or type of process that is used to present promotional messages to potential customers.