Broadband refers to networking technologies that use modulation or multiplexing to combine multiple channels for transmission over a single medium (copper telephone wire for instance). Broadband allows you to integrate data, video and voice so that it can share one line.
Broadband refers to the bandwidth of a communication channel. Bandwidth, along with signal compression, is a major determinant of the quality of the sounds/pictures transmitted along that channel. Bandwidth is measured in terms of the amount of information the carrier medium can carry, measured in bits per second (bps). The transmission capabilities of the most commonly used networks range from 64 thousand bps (64kbps) as in the case of an ordinary telephone line, to 140 million bps (140Mbps) which is the upper limit for broadcast television. The concept of broadband is a relative term. Compared with an ordinary telephone line, an ISDN2 line with 128kbps capacity used to be regarded as broadband. ADSL, running over the existing telephone network, offers superior performance with a down channel of 384 kbits/s plus a return channel of 63kbits/s.