Chapter 7 Communication Techniques

Example 7.6 Page no 304

In [4]:
#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 [1]:
#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 [1]:
#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 [9]:
#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 [10]:
#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