PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

(sharon) #1

12 Practical MATLAB® Applications for Engineers


R.1.24 The analog pulse function pul(t/τ) is illustrated graphically in Figure 1.14.
The function pul(t/τ) is defi ned analytically by


pul t

t
tt

(/ )


//


//














1for
for and




 


22


02 2





R.1.25 The analog pulse pul(t/τ) is related to the analog step function u(t) by the following
relation:


pul(t/) = u(t + /2) − u(t − /2)


R.1.26 The discrete pulse sequence denoted by pul(n/N) is given by


pul n N

Nn
Nn n

(/ )


//


//





1for
for and




 


22


02 2


N


N





For example, for N = 11 (odd), the discrete sequence is given by


pul n

n
nn

(/ ) 11


15 5


05 5











for
for
and




The preceding function pul(n/11) is illustrated in Figure 1.15.
Observe that the pulse function pul(n/11) can be represented by the superposition
of two discrete step sequences as

pul(n/11) = u(n + 5) − u(n − 6)


R.1.27 The analog unit ramp function denoted by r(t) = t u(t) is illustrated in Figure 1.16.


The unit ramp is defi ned analytically by


rt

tt
t

()


for
for







0


00





A

u(n − m)

m − 1 mm + 1m + 2m + 3

n

FIGURE 1.13
Plot of u(n − m).


pul(t/)

t
−/2 0 /2

1

FIGURE 1.14
Plot of pul(t/τ).
Free download pdf