The continued reduction of integrated circuit feature sizes and
commensurate improvements in device performance are fueling the progress
to higher functionality and new application areas. For example, over the last
15 years, the performance of microprocessors has increased 1000 times.
Analog circuit performance has also improved, albeit at a slower pace. For
example, over the same period the speed/resolution figure-of-merit of
analog-to-digital converters improved by only a factor 10.
A series of features makes the mobile telecommunications industry an
interesting field of investigation for economists: the industry is experi-
encing veryfastmarketgrowthcombinedwithrapidtechnological change;
regulatory design in setting market structure is playing a very important
role; and oligopolistic competition is unfolding under various forms. The
number of subscribers to mobile networks is growing at a rapid rate on a
worldwide basis, as shown in figure 1.1.
Sound is simply an airborne version of vibration. The air which carries sound is a mixture
of gases. In gases, the molecules contain so much energy that they break free from
their neighbors and rush around at high speed. As figure 1.1(a) shows, the innumerable
elastic collisions of these high-speed molecules produce pressure on the walls of any
gas container. If left undisturbed in a container at a constant temperature, eventually the
pressure throughout would be constant and uniform.
