from math import log10
from __future__ import division
A=60000
print "A= %0.2f"%(A) #Amplifier gain
Af=10000
print "Af= %0.2f"%(Af) #Feedback gain
N_dB=20*log10(Af/A)
print "N_dB=20*log10(Af/A)= %0.2f"%(N_dB),"dB" #Negative feedback gain
B=(1/(Af))-(1/A)# formulae using (Af=A/(1+A*B))
print "B=(1/(Af))-(1/A)= %0.2e"%(B) #Feedback factor
from __future__ import division
A=10000
print "A= %0.2f"%(A) #Amplifier gain
B=0.01
print "B= %0.2f"%(B) #Feedback factor
Af=(A/(1+A*B))
print "Af= (A/(1+A*B))=%0.2f"%(Af) #Feedback gain
A1=100000
print "A1= %0.2f"%(A1) #New amplifier gain value
Af1=(A1/(1+A1*B))
print "Af1= (A1/(1+A1*B))=%0.2f"%(Af1) #New feedback gain
from __future__ import division
Vo=(50)
print "Vo= %0.2f"%(Vo)," volts" # output voltage
Vi=(0.5)
print "Vi= %0.2f"%(Vi)," volts" # input voltage
print "part(i)"
A=Vo/Vi
print "A= Vo/Vi=%0.2f"%(A) #Amplifier gain
HD=10
print "Harmonic_distortion=%0.2f"%(HD),"%"# Percentage second harmonic distortion
D=(10*Vo)/100
print "D= (10*Vo)/100 = %0.2f"%(D)," volts" # Second Harmonic distortion
Df=(1*Vo)/100
print "Df= (1*Vo)/100 = %0.2f"%(Df)," volts" # Harmonic distortion with Feedback
B=(D/(Df*A))-(1/A) #Using formulae Df=(D/(1+A*B))
print "B=(D/(Df*A))-(1/A) = %0.2f"%(B) #Feedback factor
print "part(ii)"
Af=(A/(1+A*B))
print "Af= (A/(1+A*B)) = %0.2f"%(Af) #Feedback gain
print "part(iii)"
Vif=Vo/Af
print "Vif= Vo/Af = %0.2f"%(Vif)," volts" # New input voltage required
from __future__ import division
GBW=10**(6)
print "GBW= %0.2f"%(GBW)," Hz"# Gain-Bandwidth product
AMf=100
print "AMf=%0.2f"%(AMf) # Midband gain with feedback
fHF=GBW/AMf
print "fHF=GBW/AMf= %0.2f"%(fHF)," Hz"#Signal bandwidth
f_10percent=(10*fHF)/100
print "f_10per cent=(10*fHF)/100= %0.2f"%(f_10percent)," Hz"#Frequency below which AMf will not deviate by more than 10 percent
from __future__ import division
AM=50000
print "AM=%0.2f"%(AM) # Midband gain
fH=20*10**(3)
print "fH= %0.2f"%(fH)," Hz"# Upper cut-off frequency
fL=30
print "fL= %0.2f"%(fL)," Hz"# Lower cut-off frequency
B=5*10**(-5)
print "B= %0.2e"%(B) #Feedback factor
AMf=AM/(1+B*AM)
print "AMf=AM/(1+B*AM)=%0.2f"%(AMf) # Midband gain with feedback
fHf=fH*(1+B*AM)
print "fHf=fH*(1+B*AM)= %0.2f"%(fHf)," Hz"#Upper cut-off frequency with feedback
fLf=fL/(1+B*AM)
print "fLf=fL/(1+B*AM)= %0.2f"%(fLf)," Hz"#Lower cut-off frequency with feedback
#NOTE: calculated value of AMf is AMf=14285.714 and fLF=8.5714286 but in book given as AMf=14286 and fLF=8.58 Hz
from math import atan,pi
from __future__ import division
AM=100
print "AM=%0.2f"%(AM),"dB" # Midband gain
fc1=1*10**(4)
print "fc1= %0.2f"%(fc1)," Hz"# First Critical frequency
fc2=10**5
print "fc2= %0.2f"%(fc2)," Hz"# Second Critical frequency
fc3=10**6
print "fc3= %0.2f"%(fc3)," Hz"# Third Critical frequency
print "part(i)"
Af1=85
print "Af1=%0.2f"%(Af1),"dB" # gain at 50 kHz and -20dB/decade roll-off
f=50*10**(3)
print "f= %0.2f"%(f)," Hz"# operating frequency
theta_A=- atan(f/fc1)*180/pi- atan(f/fc2)*180/pi- atan(f/fc3)*180/pi#phase shift in radians
print "theta_A=%0.2f"%(theta_A)," degree"# Phase shift for feedback gain Af1
theta_pm=180-abs(theta_A)# formulae phase margin
print "theta_pm=180-abs(theta_A)=%0.2f"%(theta_pm)," degree"# Phase Margin for feedback gain Af1
print "Amplifier stable"# Since phase margin is (+)ive
print "part(ii)"
Af2=50
print "Af2=%0.2f"%(Af2)," dB" # gain at 500 kHz and -40dB/decade roll-off
f=500*10**(3)
print "f= %0.2f"%(f)," Hz"# frequency
theta_A=- atan(f/fc1)- atan(f/fc2)- atan(f/fc3)#phase shift in radians
theta_A=theta_A*180/pi # degree
print "theta_A= %0.2f"%(theta_A)," degree"# Phase shift for feedback gain Af2
theta_pm=180-abs(theta_A)# formulae phase margin
print "theta_pm=180-abs(theta_A)=%0.2f"%(theta_pm)," degree"# Phase Margin for feedback gain Af1
print "Amplifier unstable"# Since phase margin is (-)ive
print "part(iii)"
Af3=20
print "Af3=%0.2f"%(Af3),"dB" # gain at 1100 kHz and -60dB/decade roll-off
f=1100*10**(3)
print "f= %0.2f"%(f)," Hz"# frequency
theta_A=- atan(f/fc1)- atan(f/fc2)- atan(f/fc3)#phase shift in radians
theta_A=theta_A*180/pi # degree
print "theta_A=%0.2f"%(theta_A)," degree"# Phase shift for feedback gain Af3
theta_pm=180-abs(theta_A)# formulae phase margin
print "theta_pm=180-abs(theta_A)=%0.2f"%(theta_pm)," degree"# Phase Margin for feedback gain Af1
print "Amplifier unstable"# Since phase margin is (-)ive
#NOTE:Correct ans for part(i) phase margin ,theta_pm=71.882476 degree but in book given as 71.86 degree
# correct ans for part(iii) phase shift, theta_A=-222.01103 degree but in book given as -220.02 degree
from __future__ import division
AV=50000
print "AV=%0.2f"%(AV) # Voltage gain
Ri=50*10**(6)
print "Ri= %0.2e"%(Ri)," ohm" #Input resistance of OP-AMP
R0=1*10**(3)
print "R0= %0.2f"%(R0)," ohm" #Output resistance
AVf=10
print "AVf=%0.2f"%(AVf) # Overall Voltage gain
RSf=50*10**(3)
print "RSf= %0.2f"%(RSf)," ohm" #Source resistance
R1=RSf
RF=AVf*(R1)
print "RF=AVf*(R1)= %0.2e"%(RF)," ohm" #Feedback resistance
VS=30
print "VS= %0.2f"%(VS)," volts" # Peak-peak output swing voltage
Vomax=0.5*(VS)
print "Vomax=0.5*(VS)= -%0.2f"%(Vomax),", +%0.2f"%(Vomax)," volts" # Maximum output voltage swing at negative and positive polarities respectively
Vsmax=Vomax/AVf
print "Vsmax=Vomax/AVf= -%0.2f"%(Vsmax),", +%0.2f"%(Vsmax)," volts" # Maximum output voltage without overload clipping at both polarities
#for overall voltage gain author has used two notations 'Avf' and 'Af' ... but I am working with 'Avf' only
from __future__ import division
R1=50*10**(3)
print "R1= %0.2f"%(R1)," ohm" # resistance at input terminal of OP-AMP
RF=500*10**(3)
print "RF= %0.2f"%(RF)," ohm" #Feedback resistance
VS=1
print "VS= %0.2f"%(VS)," volts" # Peak-peak output swing voltage
print "part(i)"
print "A = infinite"# voltage gain
Vo1=-(RF/R1) #Output voltage when gain, A=infinite
print "Vo1=-(RF/R1)= %0.2f"%(Vo1)," volts"
print "part(ii)"
A=50000
print "A=%0.2f"%(A) # gain of OP-AMP
B=R1/(R1+RF)
print "B=R1/(R1+RF)= %0.2f"%(B) #Feedback factor
Vo2=-((RF)*(B*A))/(R1*(1+A*B))
print "Vo2=-((RF)*(B*A))/(R1*(1+A*B))= %0.2f"%(Vo2)," volts"# output voltage for A=50000
e=-((Vo2-Vo1)*100)/Vo1
print "%%Error,e= ((Vo2-Vo1)*100)/Vo1=%0.2f"%(e),"% "# calculation for percentage error in output voltage
print "part(iii)"
e=0.01
print "%%Error,e=%0.2f"%(e),"% "#Given percentage error in output voltage
Vo3=-(Vo1-(e*Vo1/100))
print "Vo3=Vo1-(e*Vo1/100)= %0.2f"%(Vo3)," volts"# output voltage for error 0.01%
x=Vo3*(R1/RF)
A=(x)/(B*(1-x)) #using formulae Vo=-(RF/R1)*((B*A)/1+A*B))
print "A=(Vo*R1)/(B*RF*(1-(Vo*RF/R1)))=%0.2e"%(A) # New Required gain for error less than 0.01%
# while solving the problem I have used 'e' for the error as no varriable is given for the same in textbook by author
# in textbook author has used 'Vo' for output voltage in all parts.. but to remove any ambiguity in the programe I have used 'Vo1' 'Vo2' 'Vo3' for part i, ii, iii, respectively
from math import log10
from __future__ import division
AV=100000
print "AV=%0.2f"%(AV) # Voltage gain
Ri=10*10**(3)
print "Ri= %0.2f"%(Ri)," ohm" #Input resistance of OP-AMP
Ro=10
print "Ro= %0.2f"%(Ro)," ohm" #Output resistance
Rs=10*10**(6)
print "Rs= %0.2e"%(Rs)," ohm" #Source resistance
RL=1*10**(3)
print "RL= %0.2f"%(RL)," ohm" #Load resistance
B=(Rs-Ri)/(AV*Ri)
print "B=(Rs-Ri)/(AV*Ri)= %0.2f"%(B) #Feedback factor
AVf=AV/(1+B*AV)
print "AVf=AV/(1+B*AV)=%0.2f"%(AVf) # Overall Voltage gain with feedback
Rof=Ro/(1+B*AV)
print "Rof=Ro/(1+B*AV) =%0.2f"%(Rof)," ohm" #output resistance with feedback
Rif=Ri*(1+B*AV)
print "Rif=Ri/(1+B*AV) =%0.2e"%(Rif)," ohm" #Input resistance with feedback
Ap=(AVf**2)*(Rif/RL)
print "Ap=(AVf**2)*(Rif/RL)=%0.2e"%(Ap) # Overall Power gain
AP=10*log10(Ap)
print "AP=10*log10(Ap)=%0.2f"%(AP),"dB" # Overall Power gain in dB
from math import sqrt,pi,log10
from __future__ import division
gm=10*10**(-3)
print "gm = %0.2f"%(gm)," A/V"# transconductance
Cgs=5*10**(-12)
print "Cgs= %0.2e"%(Cgs)," farad" # capacitance between gate-source
Cds=1*10**(-12)
print "Cds= %0.2e"%(Cds)," farad" # capacitance between drain-source
rd=50*10**(3)
print "rd= %0.2f"%(rd)," ohm" #Drain resistance
RG=10*10**(6)
print "RG= %0.2e"%(RG)," ohm" #Gate resistance
Rse=1*10**(3)
print "Rse= %0.2e"%(Rse)," ohm" #Gate resistance
L=0.5
print "L= %0.2f"%(L)," H" #Inductance
C2=0.05*10**(-12)
print "C2= %0.2e"%(C2)," farad" # Crystal parameter
C1=1*10**(-12)
print "C1= %0.2e"%(C1)," farad" # Crystal parameter
print "part(i)"
x=C1+((Cds*Cgs)/(Cds+Cgs))
CT=1/((1/C2)+(1/x))
print "CT= %0.2f"%(CT)," farad" # Equivalent series-resonating capacitance
print "part(ii)"
fo=sqrt(2)/(2*pi*sqrt(L*CT))
print "fo= sqrt(2)/(2*pi*sqrt(L*CT))=%0.2e"%(fo)," Hz"# frequency of oscillations
print "part(iii)"
z=sqrt((L*C1*C2)/(C1+C2))
fp=1/(2*pi*z)
print "fp= %0.2e"%(fp)," Hz"# parallel-resonant frequency
p=sqrt(L*C2)
fs=1/(2*pi*p)
print "fs= %0.2e"%(fs)," Hz"# series-resonant frequency
Q=(sqrt(L/C2))/(Rse)
print "Q=(sqrt(L/C2))/(Rse)= %0.2f"%(Q) #Quality factor
print "part(iv)"
AB=gm*rd*(Cds/Cgs)
print "AB=gm*rd*(Cds/Cgs)= %0.2f"%(AB) #Loop gain
T_bias=RG*(Cgs+Cds)
print "T_bias=RG*(Cgs+Cds)= %0.2e"%(T_bias),"s"#Bias Time-Constant
T_r = 1/(2*pi*fo)
print "T_r =1/(2*pi*fo)= %0.2e"%(T_r),"s"#resonant Time-Constant for 'fo'
print "for proper operation T_bias >> T_r"
# in part (ii)... value calculated for series resonant frequecy 'fo' is wrong in textbook.
# NOTE: in part(iii)... there is a misprint in the calculated value of Quality factor 'Q' in the textbook.
#I have used T_r instead of 1/wo (given in the book)