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diff --git a/3161/CH4/EX4.2/Ex4_2.sce b/3161/CH4/EX4.2/Ex4_2.sce
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+clc;

+//page 199

+//problem 4.2

+

+//Given angle modulated signal is x = 3*cos[2*pi*(10^6)*t+2*sin(2*pi*10^3*t)]

+

+//So, phase of the angle modulates signal is Q = 2*pi*(10^6*t)+2*sin(2*pi*(10^3)*t)

+

+//Instantaneous frequency = dQ/dt = 2*pi*(10^6)+ 4*pi*(10^3)*sin(2*pi*(10^3)*t)

+

+//For Instantaneous frequency at 0.25ms, Substituting t = 0.25ms in Instantaneous frequency

+//Instantaneous frequency is expressed as f1_rad for frequency in radians per second

+f1_rad = 2*%pi*(10^6)+ 4*%pi*(10^3)*sin(2*%pi*(10^3)*0.00025)

+

+//Instantaneous frequency is expressed as f1_hz for frequency in hertz

+f1_hz = f1_rad/(2*%pi)

+

+disp('the Instantaneous frequency at time t=0.25ms is '+string(f1_rad)+' rad/sec = '+string(f1_hz)+' Hz')

+

+//For Instantaneous frequency at 0.25ms, Substituting t = 0.5ms in Instantaneous frequency 

+//Instantaneous frequency is expressed as f2rad for frequency in radians per second

+f2_rad = 2*%pi*(10^6)+ 4*%pi*(10^3)*sin(2*%pi*(10^3)*0.0005)

+

+//Instantaneous frequency is expressed as f2hz for frequency in hertz

+f2_hz = f2_rad/(2*%pi)

+

+disp('the Instantaneous frequency at time t=0.5ms is '+string(f2_rad)+' rad/sec = '+string(f2_hz)+' Hz')

+

+//Maximum phase deviation = max[2*sin(2*pi*(10^3)*t)] = 2*1

+maxDp = 2;

+

+disp('Maximum phase deviation is '+string(maxDp)+' rad')

+

+//Maximum frequency deviation = max[4*pi*(10^3)*sin(2*pi*(10^3)*t)] = 4*pi*(10^3)*1

+maxDf = 4*%pi*(10^3)*1;

+

+disp('Maximum frequency deviation is '+string(maxDf)+' Hz')

+//disp('in rad',maxDf,'Maximum frequency deviation is')

+

+//In the textbook the calculated value of max frequency devaition is = 2000 Hz, in reality the value = 12566.371 Hz   

diff --git a/3161/CH4/EX4.4/Ex4_4.sce b/3161/CH4/EX4.4/Ex4_4.sce
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+clc;

+//page 208

+//problem 4.4

+

+//Given modulating signal m(t) = 2*sin(2*pi*(10^3)*t), B for phase modulation Bp = 10 & for fequency modulation Bf = 10

+Bp = 10

+Bf = 10

+

+//So Amplitude of modulating signal is Am=2 metres

+Am = 2

+

+//Frequency of modulating signal is fm = 1000 hertz

+fm=1000

+

+//Bandwidth = 2*(1+B)*fm

+

+//Bandwidth for phase modulation with modulating signal m(t) is bw_pm = 2*(1+Bp)*fm

+bw_pm = 2*(1+10)*1000

+

+//Bandwidth for frequency modulation with modulating signal m(t) is bw_fm = 2*(1+Bf)*fm

+bw_fm = 2*(1+10)*1000

+

+disp('Bandwidth for phase modulation '+string(bw_pm)+' Hz')

+disp('Bandwidth for frequency modulation '+string(bw_fm)+' Hz')

+

+//Bandwidth for phase & frequency modulation if frequency of modulating signal is doubled i.e fm = 2000 hertz

+

+//Bp & Bf after frequency of modulating signal is doubled

+

+//Bp = kp*Am, observing the equation as there is no change in amplitude Bp = 10

+Bp = 10

+

+//Bf = kf*Am/fm, observing the equation as there is change in frequency  Bf = 10/2 = 5

+Bf = 5

+

+//Bandwidth for phase modulation if frequency of modulating signal is doubled is bw_double_pm = 2*(1+Bp)*fm

+bw_double_pm = 2*(1+10)*2000

+

+//Bandwidth for frequency modulation if frequency of modulating signal is doubled is bw_double_fm = 2*(1+Bf)*fm

+bw_double_fm = 2*(1+5)*2000

+

+disp('Bandwidth for phase modulation for doubled frequency '+string(bw_double_pm)+' Hz')

+disp('bandwidth for frequency modulation for doubled frequency '+string(bw_double_fm)+' Hz')

+

+//Bandwidth for phase & frequency modulation if amplitude of modulating signal is halfed i.e Am = 1 metre

+

+//Bp & Bf after amplitude of modulating signal is halfed

+

+//Bp = kp*Am, observing the equation as there is change in amplitude Bp = 10/2 = 5

+Bp = 5

+

+//Bf = kf*Am/fm, observing the equation as there is change in amplitude Bf = 5/2 = 2.5

+Bf = 2.5

+

+//Bandwidth for phase modulation if frequency of modulating signal is doubled is bw_halfed_pm = 2*(1+Bp)*fm

+bw_halfed_pm = 2*(1+5)*2000

+

+//Bandwidth for frequency modulation if frequency of modulating signal is doubled is bw_halfed_fm = 2*(1+Bf)*fm

+bw_halfed_fm = 2*(1+2.5)*2000

+

+disp('Bandwidth for phase modulation for halfed amplitude '+string(bw_halfed_pm)+' Hz')

+disp('Bandwidth for frequency modulation for halfed amplitude '+string(bw_halfed_fm)+' Hz')