Chapter 35 Analog and Digital Communication

Example 35.1 Page no 978

In [4]:
#Given
Em=0.5                      
Ec=1

#Calculation
Emax=Ec+Em
Emin=Ec-Em
Ma=(Emax-Emin)/(Emax+Emin)

#Result
print"The modulation index is",Ma

The modulation index is 0.5

Example 35.2 Page no 978

In [27]:
#Given
L=3.6*10**-3                     #H
C=2.5*10**-12                    #F
Fm=15                            #KHz

#Calculation
import math
Fc=1/(2*math.pi*math.sqrt(L*C))*10**-3
S=Fc+Fm
S1=Fc-Fm

#Result
print"Frequency of upper sideband is",round(S,0),"kHz"
print"Frequency of lower sideband is",round(S1,0),"kHz"

Frequency of upper sideband is 1693.0 kHz
Frequency of lower sideband is 1663.0 kHz

Example 35.3 Page no 978

In [44]:
#Given
Fm=3.2                          #kHz
Fc=84*10**3                    #kHz
A=96                           #kHz

#Calculation
Mf=A/Fm
M1=Fc-Fm
M2=Fc+Fm

#Result
print"(a) Frequency modulation index is",Mf
print"(b) Frequency range of the modulated wave is",round(M1*10**-3,3),"*10**3 MHz","to",round(M2*10**-3,3),"*10**3 MHz"

(a) Frequency modulation index is 30.0
(b) Frequency range of the modulated wave is 83.997 *10**3 MHz to 84.003 *10**3 MHz

Example 35.4 Page no 979

In [55]:
#Given
A=1
B=2
C=0

#Calculation
Q1=(A*B**0)+(C*B**1)+(C*B**2)+(C*B**3)
Q2=(C*B**0)+(A*B**1)+(C*B**2)+(C*B**3)
Q3=(C*B**0)+(C*B**1)+(A*B**2)+(C*B**3)
Q4=(C*B**0)+(C*B**1)+(C*B**2)+(A*B**3)
Q5=(A*B**0)+(C*B**1)+(C*B**2)+(A*B**3)
Q6=(A*B**0)+(C*B**1)+(A*B**2)+(A*B**3)

#Result
print"Input voltage 0001 is",Q1,"V"
print"Input voltage 0010 is",Q2,"V"
print"Input voltage 0100 is",Q3,"V"
print"Input voltage 1000 is",Q4,"V"
print"Input voltage 1001 is",Q5,"V"
print"Input voltage 1101 is",Q6,"V"

Input voltage 0001 is 1 V
Input voltage 0010 is 2 V
Input voltage 0100 is 4 V
Input voltage 1000 is 8 V
Input voltage 1001 is 9 V
Input voltage 1101 is 13 V

Example 35.5 Page no 979

In [60]:
#Given
A=2
N=32

#Calculation
Z=A**N

#Result
print"Number of quantisation levels is",round(Z*10**-9,1),"*10**9"

Number of quantisation levels is 4.3 *10**9

Example 35.6 Page no 979

In [69]:
#Given
S=16
Q=8000

#Calculation
N=math.sqrt(S)
W=Q*N

#Result
print"The bill rate for a signal is",W,"bill s**-1"

The bill rate for a signal is 32000.0 bill s**-1