2.1 Why ever-more bandwidth?

In some instances the need for relatively large bandwidths is almost self-evident. While speech occupies only a few kilohertz of bandwidth, transmitting just one broadcast TV channel demands about 6 MHz. This is three orders of magnitude more than a single basic (analog) telephone channel. Similarly the transmission of data begins with single sources operating at perhaps 10 100 Kbps and data compression techniques are regularly used to reduce bandwidth demands.

The question is therefore acutely valid: Why is bandwidth an ever-more scarce commodity and why is there the constant pressure for more bandwidth and indeed broadband systems?

The perfectly valid question must be asked: since local bit rates are in the kilobits-per-second class such as the 51 Kbps used in practice for many 1999 2000 Internet connections why on earth are megabits per second, let alone gigabits per second, needed at all?

Part of the answer lies in the need to efficiently cram as many channels as possible into single bearers, that is, on single higher frequency carriers. Other factors include:

The cramming of multitudes of individual channels together into a form of superchannel is termed multiplexing. So there is almost always the fundamental need to multiplex in order to efficiently use the common telecommunications fabric.

If everything remained at or around 51 Kbps or 64 Kbps, then all we could possibly have...