Chapter 21 : Consumer communication systems

Example 21.1 Page No : 637

In [1]:
import math 

# Variables
D1 = 5.;

# Calculations and Results
GR1 = 3*D1**2*(1+D1);
print 'The reciever procesmath.sing gain is GR1 =  %.0f '%(GR1);

Bt = 200.*10**3;     #bandwisth in Hz
W = 53.*10**3;        #highest modulating frequency in Hz
D2 = Bt/(2*W)-1;    #deviation ratio
print 'D2 = %.3f'%(D2);

GR2 = 3*D2**2*(1+D2);
print 'The reciever procesmath.sing gain for sterio FM is GR2 =  %.3f '%(GR2);
print 'The ratio of the two gains is GR2/GR1 =  %.4f  dB'%(GR2/GR1);

dBdiffrence = 10*math.log10(GR2/GR1)
print 'dB diffrence =  %.0f dB'%(dBdiffrence);

The reciever procesmath.sing gain is GR1 =  450 
D2 = 0.887
The reciever procesmath.sing gain for sterio FM is GR2 =  4.451 
The ratio of the two gains is GR2/GR1 =  0.0099  dB
dB diffrence =  -20 dB

Example 21.2 Page No : 644

In [2]:
# Results
print 'The percentage is %.0f '%(483./525*100)

The percentage is 92

Example 21.3 Page No : 644

In [3]:
# Calculations
D = 25./15;

# Results
print 'The deviation ratio is D = %.3f '%(D)

The deviation ratio is D = 1.667

Example 21.4 Page No : 644

In [4]:
# Variables
delta_f = 25  #KHz
W = 15;      #KHz

# Calculations
Bt = 2*(delta_f+W)     #bandwidth

# Results
print 'The bandwidth is Bt = %i KHz'%(Bt)

The bandwidth is Bt = 80 KHz