# 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