WOSU-FM uses a carrier frequency of 90.5 MHz and modulating constant k f = 66,000. The speech signal utter.au is transmitted on this channel. Plot the frequency spectrum of the FM speech signal.
What will be an ideal response?
Analysis:
In MATLAB®, run the following script:
clear;
clc;
[sp, fs] = auread('utter.au');
sound(sp,fs);
kf = 66000;
Fc = 90.5e6; % Carrier frequency
Fs = 184e6; % Sampling frequency
t = 0:1/Fs:1-1/Fs;
au = interp1(0:1/fs:1-1/fs,sp,t,'spline');
for i = 1:Fs
s(i) = cos(2*pi*(Fc+ kf*cumsum(au(i)))*t(i));
end
%%
Ss = abs(fftshift(fft(s,98304))/98304);
delta = Fs/length(Ss);
faxis = -Fs/2:delta:Fs/2-delta;
figure(1)
L = length(faxis);
stem(faxis/10^6,Ss)
xlim([90.3 90.7]);
title('Frequency Spectrum of FM Signal');
xlabel('Frequency(MHz)');
ylabel('Spectrum Magnitude');
It plays the audio signal and compute the FM signal. The spectrum of the FM signal is plotted and shown as follows. The peak centers at the carrier frequency, 90.5MHz.
Trades & Technology
You might also like to view...
The event that will MOST-Likely occur when excess oil runs out of the input shaft and onto the clutch disc is:
A. clutch free play B. clutch failure C. chattering clutch D. gravity bleeding
Trades & Technology
Subcontractors often perform ____% or more of the work on building construction projects.
A. 65 B. 70 C. 75 D. 80
Trades & Technology
Which population groups have a greater risk of developing severe complications from zoonotic disease?
What will be an ideal response?
Trades & Technology
A long block can be made from a short block with the addition of ________
A) Cylinder heads and valve train B) Oil pump, oil pan, and timing chain cover C) Fuel pump, carburetor, and air cleaner assembly D) Intake and exhaust manifolds
Trades & Technology