MATLAB PROBLEM We wish to transmit the following 20 bits of

MATLAB PROBLEM:

We wish to transmit the following 20 bits of data, using various modulation schemes: [1 0 0 1 1 1 0 1 1 0 0 0 0 1 0 1 1 1 0 1]

1. Using a data rate of 1 bit per second, a carrier of 5 Hz., and a sampling frequency of 50 samples per second, create a MATLAB plot of the OOK modulated signal, along with a plot of the PSD of the signal. Use the functions \"plot_fft_spectrum\" and \"fft_spectrum\" as a starting point, and modify as necessary.

2. Repeat for BPSK

3. Now create an FSK modulation of the same signal, using 4 Hz. and 6 Hz. to represent binary zeros and ones respectively.

**********Submit the 3 plots. Make sure all axes are labeled properly.

ANSWER THE THIRD PART(3) ONLY PLEASE

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% \"plot_fft_spectrum\"

function [f,X] = fft_spectrum(t,x)
%this function uses the built-in fft to compute the frequency spectrum of a
%signal x. It also generates the appropriate frequency scale, f, and
%applies the \"fftshift\" so that X and f vectors are available directly for
%plotting.

%the inputs x and t should be vectors of the same length.

%the outputs, X and f will also be vectors of that length

%this program is very simple, and will only work if the time axis either starts with 0, or is
%balanced positive and negative, with 0 in the center.

%extract the parameters of t vector
N=length(x);
dt=t(2)-t(1);
%create frequency vector
df=1/(N*dt);
%note the difference between odd length and even length vectors
if rem(N,2)==0 %N even
f= ( (-N/2):(N/2-1) )*df;
else %N odd
f= ( (-(N-1)/2):((N-1)/2) )*df;
end
%find the index of the t=0 element
N0=find(t==0);

%do the fft to create the spectrum samples
%use proper shifting depending on the time scale and scale amplitude by dt
if N0==1 %time scale is nonnegative
%X=fftshift(fft(fftshift(x)))*dt;
X=fftshift(fft((x)))*dt;
elseif rem(N,2)==0 && N0==N/2+1 %time scale is balanced, N is even
X=fftshift(fft(x))*dt;
elseif rem(N,2)==1 && N0==(N+1)/2 %time scale is balanced, N is odd
X=fftshift(fft(x))*dt;
else %time scale is unbalanced, so this function won\'t handle it
disp(\'Unbalanced time scale.\')
end

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% \"fft_spectrum\"

function [f,X] = plot_fft_spectrum(t,x,fignum)
%this function calls fft_spectrum to compute the fft of an arbitrary
%signal, and plot the magnitude and phase spectrum
%It calls the function fft_spectrum to do the computation

%INPUTS
%t is the vector of time samples on which x is defined
%x is the vector of samples of the function x(t)
%fignum is the figure number you wish MATLAB to plot in

%compute the spectrum and the frequency axis values
if t(1)==0 %positive time scale
[f,X]=fft_spectrum(t,x);
else %balanced time scale, so put the t=0 value in the first element
[f,X]=fft_spectrum(t,fftshift(x));
end

figure(1), clf
subplot(3,1,1), plot(t,x,\'b\',\'LineWidth\',2)
title(\'Time Signal\')
ylabel(\'x(t)\')
xlabel(\'Time (seconds)\')
grid on
subplot(3,1,2), plot(f,abs(X),\'b\',\'LineWidth\',2)
title(\'Magnitude Spectrum\')
ylabel(\'|X(f)|\')
xlabel(\'Frequency (Hz.)\')
axis([min(f) max(f) 0 1.2*max(abs(X))])
grid on
subplot(3,1,3), plot(f,angle(X),\'r\',\'LineWidth\',2)
title(\'Phase Spectrum\')
ylabel(\'\\Phi(X(f))\')
xlabel(\'Frequency (Hz.)\')
grid on
% subplot(5,1,4), plot(f,real(X),\'b\')
% grid on
% subplot(5,1,5), plot(f,imag(X),\'r\')
% grid on

**********Submit the 3 plots. Make sure all axes are labeled properly.

Solution

ent of the regulating signal. The data transfer capacity required is two circumstances the most astounding recurrence content including any sounds for parallel heartbeat tweaking signals.

Recurrence move scratching (FSK) shifts the bearer between two distinct frequencies called the stamp and space frequencies, or fm and fs(Fig. 1c). FM delivers various sideband frequencies above and beneath the bearer recurrence. The data transfer capacity created is an element of the most elevated regulating recurrence including sounds and the balance file, which is:

m = f(T)

f is the recurrence deviation or move between the check and space frequencies, or:

f = fs – fm

T is the bit time interim of the information or the proportional of the information rate (1/bit/s).

Littler estimations of m deliver less sidebands. A prevalent form of FSK called least move keying (MSK) indicates m = 0.5. Littler qualities are likewise utilized, for example, m = 0.3.

Here are two approaches to additionally enhance the phantom proficiency for both ASK and FSK. To begin with, select information rates, transporter frequencies, and move frequencies so there are no discontinuities in the sine bearer when changing starting with one double state then onto the next. These discontinuities create glitches that expansion the consonant substance and the data transmission.

The thought is to synchronize the stop and begin times of the paired information with when the sine transporter is transitioning in abundancy or recurrence at the zero intersection focuses. This is called consistent stage or lucid operation. Both cognizant ASK/OOK and reasonable FSK have less music and a smaller transfer speed than non-intelligible signs.

A moment method is to channel the twofold information before balance. This adjusts the flag off, protracting the ascent and fall times and lessening the consonant substance. Uncommon Gaussian and raised cosine low pass channels are utilized for this reason. GSM mobile phones broadly utilize a prevalent mix, Gaussian sifted MSK (GMSK), which permits an information rate of 270 kbits/s in a 200-kHz channel.

Parallel Phase Shift Keying (BPSK) And Quadrature Phase Shift Keying (QPSK)

An exceptionally mainstream computerized regulation plan, twofold stage move scratching (BPSK), shifts the transporter sine wave 180° for each adjustment in double state (Fig. 2). BPSK is sound as the stage moves happen at the zero intersection focuses. The best possible demodulation of BPSK requires the flag to be contrasted with a sine bearer of a similar stage. This includes transporter recuperation and other complex hardware.