operations of signals

1. Operations of Signals
By
Md. Fazle Rabbi
16CSE057

2. 4.2
Introduction To Signal
 A Signal is the function of one or more independent
variables that carries some information to represent a
physical phenomenon
 A continuous-time signal, also called an analog signal, is
defined along a continuum of time

3. 4.3
Operations of Signals
1. Time shifting
2. Time reversal
3. Time scaling
4. Signal addition
5. Signal multiplication

4. 4.4
Time Shifting
x(t ± t0) is time shifted version of the signal x(t).
x (t + t0) → negative shift
x (t - t0) → positive shift

5. 4.5
Time Scaling
x(At) is time scaled version of the signal x(t).
where A is always positive.
|A| > 1 → Compression of the signal
|A| < 1 → Expansion of the signal

6. 4.6
Time Scaling Cont.
Example: Given x(t) and we are to find y(t) = x(2t)
The period of x(t) is 2 and the period of y(t) is 1,

7. 4.7
Time Reversal
Time reversal is also called time folding
In Time reversal signal is reversed with respect to
time i.e.
y(t) = x(-t) is obtained for the given function

8. 4.8
Signal Addition
 In discrete-time domain, the sum of two signals x1(n) and x2(n)
can be obtained by adding the corresponding sample values .
 the subtraction of x2(n) from x1(n) can be obtained by
subtracting each sample of x2(n) from the corresponding sample
of x1(n) as illustrated below.
If
x1(n) = {1, 2, 3, 1, 5} and x2(n) = {2, 3, 4, 1, –2}
Then
x1(n) + x2(n) = {1 + 2, 2 + 3, 3 + 4, 1 + 1, 5 – 2} = {3, 5, 7, 2, 3}
and
x1(n) – x2(n) = {1 – 2, 2 – 3, 3 – 4, 1 – 1, 5 + 2}
= {–1, –1, –1, 0, 7}

9. 4.9
Signal Multiplication
The multiplication of two discrete-time sequences can be
performed by multiplying their values at the sampling
instants as shown below.
If x1(n) = {1, –3, 2, 4, 1.5} and
x2(n) = {2, –1, 3, 1.5, 2}

10. 4.10
Thank You