narrow band versus wideband communications
Dear Masadi,
In Digital Communications, Wideband is a bandwidth class between 64Kbps and 1.544Mbps whereas Narrowband is only up to 64Kbps. Should a communication device, a circuit or a channel of a certain network (usually wireless) exhibit a bandwidth of at least 64Kbps, it is termed Wideband. It is however not the carrier frequency to determine a device, a circuit or a channel as Wideband. Thus a Wideband entity can also range from DC to 32KHz, assuming 2bps.
In RF and Analog circuits, Gain-Bandwidth Product is a basic relationship. 1 Octave specifies an 2 times increase in bandwidth for a device or a circuit at the expense of a reduced gain. This only specifies a wider band, hence not necessary a Wideband. Therefore an entity subjected to 1 Octave change in bandwidth must first satisfy a bandwidth of at least 64Kbps to be considered Wideband.