Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
19. What is analogtodigital conversion of signals?
A discretetime signal is defined by specifying its value only at discrete
times, called sampling instants. When the sampled values are quantised and
encoded, a digital signal is obtained. A digital signal is obtained from the
analog signal by using an analogtodigital converter. This entire process is
referred to as the conversion of signals from analog to digital form.
20. What are the properties of ROC for zTransform?
Properties of the ROC for the zTransform :
1. X(z) converges uniformly if and only if the ROC of the ztransform X(z) of
the sequence includes the unit circle. The ROC of X(z) consists of a ring in
the zplane centered about the origin. That is, the ROC of the ztransform of
x(n) has values of z for which x(n) rn is absolutely summable.
2. The ROC does not contain any poles.
3. When x(n) is of finite duration then the ROC is the entire zplane, except
possibly z=0 and/or z=infinity.
4. If x(n) is a right sided sequence, the ROC will not include infinity.
5. If x(n) is a left sided sequence, the ROC will not include z=0. However if
x(n)=0 for all n>0, the ROC will include z=0.
6. If x(n) is two sided and if the circle z = r0 is in the ROC, then the ROC
will consist of a ring in the zplane that includes the circle z=r0.
7. If X(z) is rational, then the ROC extends to infinity, i.e. the ROC is
bounded by poles.
8. If x(n) is causal, then the ROC includes z=infinity.
9. If x(n) is anti causal, trhen the ROC includes z=0.
Part
1
Part 2
Part 3
Part 4
Part 5
Part 6
