Day 3

Day 3 - Spectral analysis

Today the day was fun because it felt like we are using deeper matlab functions and it starts to get complicated.  We analysed signals using the FFT and the dB -scale. Those signals of course had to be generated or imported first. We also got a look at the sptool and the spectrogram.

done:

• Reworked Excercise 2

• Excercise 3 - Spectral analysis, solved all the questions in teamwork, for team-document click here

• Wrote a script which animates the ongoing frequency changes

 

• Created a lot of signals and its Fourier transformations while using the dB-scale

FFT of 2 sine signals using the dB-Scale

• created random signals which showed noises in the frequency domain as seen in the video above

• imported sounds/files into the sptool 

•  created a spectrogram of the sputnik sound file

Spectrogram - Sputnik sound

• worked : (13h) + 7h = 20h

learned:

• How to use the fft in Matlab and display its results using the dB-scale

• Create signals with and without noise.

• Using the For-loop to create animated plots

• Also learned how to differentiate between signals using the FFT and the dB-scale

• How to import .wav files into Matlab and analyse them using the Sptool or the Spectrogram.

• understood Aliasing 100%

to do (next):

• Get used to the parameters of the spectrogram (window, fs e.t.c.)

• Create Filters with the sptool

• Use Filters to avoid for example aliasing or to get the noise out of a signal