[Solved] CS6300 Speech Technology: Laboratory 2 & 3

Generate two sinusoids at two different frequencies ₀ and ₁ (512 samples). Convolve the two signals. Compute DFT of the convolved signal. Plot the spectrum. Compute the DFT of each of the signals. Multiply the spectra, and compare them with that of the convolved signal. Remember that the DFT order should be >= length of the signal.

1. Record isolated vowels from both yourself and your partner. Compute theDFT spectrum. Find the first two prominent peaks, say F₁,F₂. Plot F₁ F₂.
2. Record unvoiced (UA, A) /k/ /tch/ /t/ /th/ /p/ and their voiced counterparts. Produce all the sounds by suffixing with vowels /a/, /i/ and /u/. Compare the corresponding time domain signals.
3. Record diphthongs /ai/ and /ao/. Plot the spectrogram. Compare thespectrograms with that of the individual spectrograms of the original vowels. Experiment with window sizes that include just one pitch period vs. another that includes at least two pitch periods.
4. Record fricatives /s/ and /h/ by suffixing with vowel /a/. Compare thespectrograms, and record the same.
5. Generate a set of tones in the range 350-440Hz (fixed amplitude). Makea composite signal by adding all these tones. This is called the masking noise. Next generate a fixed frequency tone from 100 Hz to that of 3000 Hz. Change the amplitude of the tone until the tone is just discernible. Plot the tone amplitude as a function of frequency.
6. Record an arbitrary sentence containing all the vowels you have recordedso far. Mark the boundaries using audacity. Estimate F₁,F₂ for the vowels. Compare the histograms of the vowel frequencies with that obtained in Question 2.

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