Chapter 6 FM Circuits

Example 6.1 Page no 178

In [1]:
#Given
Vc =40*10**-12
c = 20*10**-12
f0 = 5.5*10**6
Ct = Vc+c

#Calculation
L = 1/((6.28*f0)**2*Ct)

#Result
print"The value of the inductance is ",round(L*10**6,0),"microhenry"

The value of the inductance is  14.0 microhenry

Example 6.2 Page no 186

In [2]:
#Given
f=168.96*10**6
multiplier=24.0
deviation = 5*10**3
fm = 2.8*10**3

#Calculation
f0 =f/multiplier
fd= deviation/multiplier
phaseshift = fd/fm
phaseshift_degrees = phaseshift*57.3
total_phaseshift =2*phaseshift_degrees

#Result
print"(a) The crystal oscillator frequency is ",f0/10**6,"MHz"
print"(b) The total phase shift is ",round(total_phaseshift,3),"degree"

(a) The crystal oscillator frequency is  7.04 MHz
(b) The total phase shift is  8.527 degree

Example 6.3 Page no 187

In [5]:
#Given
R =1*10**3
phaseshift =4.263
phaseshift_center= 45
f =7.04*10**6

#Calculation
phase_l = phaseshift_center - phaseshift
phase_u = phaseshift_center + phaseshift
phaserange_total = phase_u - phase_l
Xc1 = 1161
C1 = 1/(6.28*f*Xc1)
Xc2 = 861
C2 = 1/(6.28*f*Xc2)

#Result
print"The two values of the capacitance to achieve total deviation are ",round(C1*10**12,1),"pf to",round(C2*10**12,1),"pf"

The two values of the capacitance to achieve total deviation are  19.5 pf to 26.3 pf