Matlab: Analysis of signal

I have a problem with this task:

For free route perform frequency analysis and give parametrs of each signal component:

• time of beginning and ending of each component
• beginning and ending frequency
• amplitude (in time domain) in the beginning and end of each signal's component
• level of noise in dB

Assume开发者_如何转开发, that, the parametrs of each component like amplitude, frequency is changing lineary in time. Frequency of sampling is 1000Hz

For example I have signal like this:

Nx=64;
fs=1000;
t=1/fs*(0:Nx-1);

%==========================
A1=1;
A2=4;
f1=500;
f2=1000;

x1=A1*cos(2*pi*f1*t);
x2=A2*sin(2*pi*f2*t);
%==========================
x=x1+x2;

you are horrendously under-sampling your signal. You will be able to see your 500Hz sin wave, but just barely and your 1000Hz sine-wave wont appear where you would like it to. You will have aliasing issues.

You are also not going to see too many samples (64 samples is not enough data) MaxTime = 1;%second; fs = 2000; %minimum for shannon-nyquist t = 0:1/fs:MaxTime; %this ensures that you are getting the correct sampling rate and you can adjust the time range.

Noise Level = -infinity dB (there is no noise component here)