# Chapter 7 Communication Techniques¶

## Example 7.6 Page no 304¶

In :
#given
Q=60
IF=455*10**3
x=680.0*10**3

#calculation
import math
imf=x+2*(IF)              #image frequency
a=(imf/x)
b=(x/imf)
c=(Q*(a-b))
d=20*math.log10(c)

#result
print"The image frequency is ",imf,"Hz"
print"image rejection = ",round(d,3),"dB"

The image frequency is  1590000.0 Hz
image rejection =  41.186 dB


## Example 7.7 Page no 314¶

In :
#given
NF=20.0
df=10**6

#calculation
x=10*math.log10(df)
S=-174+NF+x
a=5                           #input intercept
dr=2/3.0*(a-S)

#result
print"S= ",S,"dB"
print"dynamic range= ",dr,"dB"

S=  -94.0 dB
dynamic range=  66.0 dB


## Example 7.8 Page no 315¶

In :
#given
nf=5.0
x=24.0
y=20.0

#calculation
import math
NR0=10**(nf/10.0)
NR1=10**(y/10.0)
PG1=10**(x/10.0)
NR=NR0+((NR1-1)/PG1)
NF=10*math.log10(NR)
S=-174+NF+60
a=nf-x                             #the system's third-order intercept point
dr=2/3.0*(a-S)

#result
print"NR1 = ",round(NR0,3)
print"NR2 = ",NR1
print"PG1=  = ",round(PG1,3)
print"NR = ",round(NR,3),"dB"
print"NF = ",round(NF,3),"dB"             #total system noise figure
print"S = ",round(S,3),"dBm"             #sensitivity
print"the systems third-order intercept point is",a,"dB"
print"dynamic range = ",round(dr,1),"dB"

NR1 =  3.162
NR2 =  100.0
PG1=  =  251.189
NR =  3.556 dB
NF =  5.51 dB
S =  -108.49 dBm
the systems third-order intercept point is -19.0 dB
dynamic range =  59.7 dB


## Example 7.9 Page no 315¶

In :
#given
x=24
nf=-5
NR = 3.16+(99/10.0)

#calculation
import math
NF = 10*math.log10(NR)
S=-174+NF+60
dr = 2/3.0*(nf-S)

#result
print"NR = ",NR                #noise ratio
print"NF = ",round(NF,3),"dB"             #noise figure
print"S = ",round(S,3),"dBm"            #sensitivity
print"dynamic range = ",round(dr,3),"dB"

NR =  13.06
NF =  11.159 dB
S =  -102.841 dBm
dynamic range =  65.227 dB


## Example 7.10 Page no 329¶

In :
#given
x=0.40*100*10**6
y=(100*10**6/(2.0**32))
#fCLK is reference oscillator

#result
print"The maximum output frequency is approximately 40 percent of fCLK MAX",x,"Hz"
print"The frequency resolution is given by ",round(y,3),"Hz"

The maximum output frequency is approximately 40 percent of fCLK MAX 40000000.0 Hz
The frequency resolution is given by  0.023 Hz