Question

Help solve in MATLAB

1. Let m(t) be the 2-bit modulating signal and s(t) cos(at) be carrier signal as shown in Figure 3. Plot these two signals in 2 separated figures using MATLAB with a, = 600Or rad/s and t = 0:7, :0.01 sec where fs = 10MHz be the sampling rate to satisfy Nyquist theorem. Use the zoom in tool of MATLAB to clearly look at the signal if necessary. You can use the MATLAB function below to produce the modulating signal m(t)

Answer 1

Hi,

As per the problem statement, Please find the solution below with in-lined comments:

Note: included zoom feature , As no mentioned like specific zoom requirements , basic zoom on implemented on both plots

Program1: Describes the Plot for Time Vs Modulation Signal as follows:

ModulationSignalPlot.m

% Plot for time Vs 2-bit modulation signal as follows % Given frequency   in MHz so converting into Hz % 1MHz = 10^6 Hz fx = 10^6; % Given time range t = 0:1/fx:0.01; % no of bits n = 2; % Finding the Modulating signal as follows mt = ASK_Modulating_signal(n,t); %Plot Time Vs Modulating signal plot(t,mt,'r'); zoom on; xlabel('Time (sec)'); ylabel('Modulation signal'); title('Time Vs Modulation ');

Please find the output below:

Program2: Plot from Time Vs Carrier Signal as follows:

CarrierSignalPlot.m

% Plot Time Vs Carrier Signal as follows % Given frequency   in MHz so converting into Hz % 1MHz = 10^6 Hz fx = 10^6; % Given time range t = 0:1/fx:0.01; % Given constant wc = 6*10^3*pi; % Given Carrier Signal function st = cos(wc.*t); %Plot Time Vs Modulating signal plot(t,st,'g'); zoom on; xlabel('Time (sec)'); ylabel('Carrier signal'); title('Time Vs Carrier');

Please find the output below:

Please find the ASK_Modulating_signal.m for reference:

function [mt] = ASK_Modulating_signal(n,t) Amp_level = 0:1/(n-1):1; mt = zeros(1,length(t)); lm = round(10000*rand(1, length(Amp_level))); Idmx = round(length(t)*rand(1, length(Amp_level))); for i=1:length(lm)     if Idmx(i) < lm(i)       lm(i) = round(Idmx(i)/3);     end         if Idmx(i)+lm(i)/2 > length(t)       mt(1,Idmx(i)-round(lm(i)/2):length(t)) = Amp_level(i);     else       mt(1,Idmx(i)-round(lm(i)/2):Idmx(i)+round(lm(i)/2)) = Amp_level(i);     end end end

Thanks