Fundamental Frequency and Periodicity

Fundamental Frequency and Periodicity

1

Lab:

Fundamental Frequency and Periodicity

Installing SpeechTool/Ztool

  1. From bug the ‘SpeechTool’ link under “Research, Publications, Software”.

This is a standard installation script. You’re better off if you let the installer figure out where to put the software (‘c:\ztool’). You can put it anywhere you want, but if you end up having problems it may be less likely that I can help you.

  1. Run SpeechTool (or let the installer start it for you)
  1. Before you do anything else, on the top row of buttons, bug the 6th button from the left. It’s next to the arrow and looks a little like an upper case ‘I’. (You only have to do this once.)
  1. UnderSpeechTool’s ‘Edit’ menu, pick preferences, then choose the ‘Sizes’ tab. Set ‘Aspect ratio’ to something like 0.4 or 0.5. (You only have to do this once also.)

Running the f0 and Periodicity Lab

  1. File>Open (or bug the folder icon). This is a standard Windows dialog box. Navigate around until you find ‘c:\ztool\av.wav’. SpeechTool will display the time domain signal for the utterance, “Avacados have large pits” (which they do).
  1. Click the ‘Slice’ button. A detailed version (50 ms) of the full sound wave will be displayed. Notice that as you move the cursor left and right over the top display – the full waveform – the ‘slice’ will be updated, showing you a detailed version of the full waveform centered at the location of the cursor. (If the display does not update as you move, click the furthest button in the top row – the one that looks like two sinewaves.)
  1. Click anywhere on the top display. Its title bar will turn yellow. Then bug the ‘BBGram’ button to get a broadband spectrogram.
  1. Click again on the top display and bug the ‘NBGram’ button to get a narrowband spectrogram.
  1. With the narrowband gram highlighted (i.e., yellow title bar), click the ‘Slice’ button. This gives you a slice of the nb gram at the cursor location. Note again that the slice is updated as you move the cursor over either a gram or the time waveform.
  1. On the waveform display at the top, position the cursor at about the midpoint of the 1st vowel (the  of ‘avacado’).
  1. By looking at the waveform slice, what kind of signal is this (simple periodic, …)?

______

  1. How did you know?
  1. By looking at the narrowband spectral slice, what kind of signal is this (simple periodic, …)?

______

  1. How did you know?
  1. On the waveform display at the top, position the cursor at about the midpoint of the  of . The  starts at about 390 ms (see the ‘x’ value in the lower right corner of the SpeechTool pane).
  1. By looking at the waveform slice, what kind of signal is this (simple periodic, …)?

______

  1. How did you know?
  1. By looking at the narrowband spectral slice, what kind of signal is this (simple periodic, …)?

______

  1. How did you know?
  1. Turn off the ‘continuous report’ feature by bugging the button in the upper right that looks like two sinusoids. As you move the cursor left and right over waveform or spectrogram displays, slices will not automatically update. To get the slices to update, you now have to click on a waveform or gram. Now, click the waveform at the top at about the midpoint of the first [ɑ] of [ɑvəkɑdo] (about 185 ms).
  1. Move to the waveformslice and position the cursor as close as you can to a prominent positive peak in the wave. (See the screen dump on the last page.) Click the mouse and look at the data in SpeechTool’s lower left corner. It will say something like, “Nearest peak=(185.75,24008.1)”. The 185.75 is the time (in ms) corresponding to that wave peak. (The 2nd value does not matter.)
  1. Move the cursor back exactly one cycle and locate the corresponding positive peak in the previous cycle. Click the mouse and read the data in the lower left corner. You will see something like “Nearest peak=(176.42,19008.7)”. Subtract the two numbers to get the fundamental period (185.75-176.42=9.33), then convert to fundamental frequency (1.0/0.00933=107.18 Hz).

What value did you get? ______

  1. Optional: increase the height of the spectral slice by grabbing the bottom border and pulling down. Click the waveform at the top at about the midpoint of the first [ɑ] of [ɑvəkɑdo] (about 185 ms).
  1. Move to the spectral slice and position the cursor as close as you can to the first harmonic peak. Click the mouse and look at the data in SpeechTool’s lower left corner. It will say something like, “Nearest peak=(105.6,1965.4)”. The 105.6 is the frequency of the 1st harmonic. (Again, the 2nd value does not matter.)

What value did you get for f0? ______

Is this pretty close to the value you got using the time-domain method in #8? ______

  1. Position the cursor as close as you can to the second harmonic peak. Click the mouse and look at the data in SpeechTool’s lower left corner. It will say something like, “Nearest peak=(210.8,4072.2)”. The 210.8 is the frequency of the 2nd harmonic.

What value did you get? ______

Is this value pretty close to f0 x 2? ______

Is the harmonic spacing (i.e., the difference between H1 and H2) pretty close to the value you got for f0? ______

  1. Repeat step 8 for the 2nd[ɑ] of [ɑvəkɑdo](~513 ms). What value did you get? ______
  1. Repeat step 9 for the 2nd[ɑ] of [ɑvəkɑdo](~513 ms).
  1. What value did you get for f0? ______
  1. Is this pretty close to the value you got using the time-domain method in #9? ______
  1. What value did you get for H2? ______
  1. Is this value pretty close to f0 x 2? ______
  1. Is the harmonic spacing (i.e., the difference between H1 and H2) pretty close to the value you got for f0? ______

Top View