Hardware and software availability
It is often the case in engineering that we know of an optimum design of a system,
but do not yet have the technology invented or sufficient processing power to implement
it.
A recent example in data communications is the new digital cellular system GSM,
where the modulation format GMSK (Gaussian Minimum Shift
Keying) was chosen, rather than the technically superior QPSK
format, owing to the problems with realizing a cost, and power efficient linear power
amplifier required by QPSK in the handsets. (Subsequently, suitable amplifiers have been
invented and the latest cellular system proposals use QPSK.)
Digital signal processors (very fast special-purpose microprocessors) are now being used
in many applications to implement functions traditionally realized using hardware
components. In fact most high-speed telephone modems are implemented in digital signal
processing. The processing power of these devices is increasing approximately 2-3
fold every year.
|
 |