glenjoy
Banned
- Joined
- Jan 1, 2004
- Messages
- 962
- Helped
- 72
- Reputation
- 146
- Reaction score
- 20
- Trophy points
- 1,298
- Location
- Philippines
- Activity points
- 0
Signals, Spectra and Signal Processing
Remedial
This remedial exam is composed of four numbers. Each number is equivalent to the its corresponding major examination.
Make sure that all the plots have labels on each axis and a title. Use xlabe, ylabel and title. Place your MATLAB commands on the answer sheet .
1. (Prelim (10%)) Generate the following signals and plot each one with respect to time.
a. 128 samples of a sinusoid with frequency of 440 Hz, amplitude of 0.8; sampling rate is 8000 Hz;
b. 250 ms of an exponentially decaying signal with a time constant of 50 ms; sampling rate is 1000 Hz;
c. Compare the lengths of the signals in a. and b., and zero-pad the end of the signal with shorter length such that the two signals will have the same length. Multiply the two signals.
d. Compare the lengths of the signals in a. and b., and truncate the signal with longer length such that the two signals will have the same length. Multiply the two signals.
2. (Midterm (20%)) [Z-Transform problems] Using MatLab, solve the following problems from Proakis and Manolakis 3rd ed.
a. 3.2 (g)
b. 3.3 (d)
c. 3.7
d. 3.14 (j)
e. 3.15
3. (Prefinals (10%)) Using the routine ‘fft’, determine the number and relative amplitudes of harmonics in sound1.wav, and plot the following:
a. mesh of the specgram of sound1.wav using an FFT-length of 128 and a corresponding Hamming window, with no overlaps
b. waterfall of the specgram of sound1.wav using an FFT-length of 256 and a corresponding Hamming window, with overlap of 128
Do you see the same number and relative amplitudes in the mesh, waterfall and fft? If not, what is the difference?
4. (Finals (20%))
a. Multiply the signal sound1.wav with a 5 Hz sinusoid. Plot the resulting signal’s time-domain waveform and the spectrum. Are the results consistent with the modulation theorem? Why and why not?
b. Take the Fourier transform of sound1.wav. Shift all the frequency components by +100 Hz and take the inverse Fourier transform of the shifted sinusoids. Plot the resulting signal’s time-domain waveform. Is the result consistent with the modulation theorem? Why and why not?
Remedial
This remedial exam is composed of four numbers. Each number is equivalent to the its corresponding major examination.
Make sure that all the plots have labels on each axis and a title. Use xlabe, ylabel and title. Place your MATLAB commands on the answer sheet .
1. (Prelim (10%)) Generate the following signals and plot each one with respect to time.
a. 128 samples of a sinusoid with frequency of 440 Hz, amplitude of 0.8; sampling rate is 8000 Hz;
b. 250 ms of an exponentially decaying signal with a time constant of 50 ms; sampling rate is 1000 Hz;
c. Compare the lengths of the signals in a. and b., and zero-pad the end of the signal with shorter length such that the two signals will have the same length. Multiply the two signals.
d. Compare the lengths of the signals in a. and b., and truncate the signal with longer length such that the two signals will have the same length. Multiply the two signals.
2. (Midterm (20%)) [Z-Transform problems] Using MatLab, solve the following problems from Proakis and Manolakis 3rd ed.
a. 3.2 (g)
b. 3.3 (d)
c. 3.7
d. 3.14 (j)
e. 3.15
3. (Prefinals (10%)) Using the routine ‘fft’, determine the number and relative amplitudes of harmonics in sound1.wav, and plot the following:
a. mesh of the specgram of sound1.wav using an FFT-length of 128 and a corresponding Hamming window, with no overlaps
b. waterfall of the specgram of sound1.wav using an FFT-length of 256 and a corresponding Hamming window, with overlap of 128
Do you see the same number and relative amplitudes in the mesh, waterfall and fft? If not, what is the difference?
4. (Finals (20%))
a. Multiply the signal sound1.wav with a 5 Hz sinusoid. Plot the resulting signal’s time-domain waveform and the spectrum. Are the results consistent with the modulation theorem? Why and why not?
b. Take the Fourier transform of sound1.wav. Shift all the frequency components by +100 Hz and take the inverse Fourier transform of the shifted sinusoids. Plot the resulting signal’s time-domain waveform. Is the result consistent with the modulation theorem? Why and why not?