# Chapter 4 single-sideband communication¶

## Example 4.1 Page no 172¶

In :
#given
x=1*10**6           #DSB range
y=10**(80/20.0)

#calculation
import math
z=math.sqrt(y)
df=200.0
Q=(x*z)/(4.0*df)
a=100*10**3
Q1=(a*z)/(4.0*df)

#result
print"(a) Q for 1MHz  = ",Q
print"(b) Q for 100KHz = ",Q1

(a) Q for 1MHz  =  125000.0
(b) Q for 100KHz =  12500.0


## Example 4.2 Page no 178¶

In :
#given
a=3*10**6
b=3.1*10**6                  #new DSB signal range
c=2.9*10**6                  #new DSB signal range

#calculation
Q=(a/(b-c))

#result
print"the required filter Q is = ",Q

the required filter Q is =  15.0


## Example 4.4 Page no 187¶

In :
#given
a=455
x=2000+1     #frequency
y=2000+3     #frequency

#calculation
c=2000+a      #local oscillator value
d=c-x
e=c-y
f=a-454
g=a-452

#result
print"RF =",x,"KHz", "at which first mixer input=" ,y,"kHz"
print"local oscillator value is ",c,"KHz"
print"First mixer output is",d,"to",e,"KHz"                #IF amp and second mixer input
print"BFO = ",a,"KHz"
print"Second mixer output is",f,"KHz", "and audio amplifier value is =",g, "kHz"

RF = 2001 KHz at which first mixer input= 2003 kHz
local oscillator value is  2455 KHz
First mixer output is 454 to 452 KHz
BFO =  455 KHz
Second mixer output is 1 KHz and audio amplifier value is = 3 kHz