Re: linearity
mince,
There a couple of ways to define linearity. For amplifiers, perhaps the easiest and most intuitive is the following:
. If a plot of the output vs input is a straight line, then
. the system is linear
.
For amplifiers, a more mathematical description is:
.
For any function of x f(x):
If f(a+b) = f(a) + f(b), then the system is linear.
.
For filters, linearity refers to phase linearity:
If the phase shift of a filter is directly proportinal to frequency, then the filter has phase linearity. An implication of this is the all frequencies are delayed an equal amount with respect to time, and ther will be no waveform distorion.
Regards,
Kral