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== Spectrograms== | == Spectrograms== | ||
| − | + | Spectrograms are used to show spectral density.It has a horizontal axis of time,a vertical axis showing the frequency and a third axis showing the intensity.For a given spectrogram S, the strength of a given frequency component f at a given time t in the speech signal is represented by the darkness or color of the corresponding point S(t,f).The color red depicts high intensity and yellow, green shows medium intensity and blue hows low intensity ,gray and gradually white depicts that the intensity is under the threshold level.Spectrograms are based on Short Time Fourier Transform(STFT),where the input signal is broken down into blocks and then DFT of each block is take and averaged to find the spectral density.Generally Spectrograms are done in gray scale,where the darkness of a plot represents the high intensity regions. | |
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Revision as of 22:46, 28 October 2009
Contents
Human Vocal system and properties
In case of Humans
Male and female voice characterstics
The 2 vocal properties are intensity(loudness) and frequency(pitch).Pitch of a man's voice fall under low frequency,where as woman's voice is of the high pitch type.Pitch and intensity are proportional to each other. As seen in the spectrograms beneath,we can compare the intensities of male vs female voice.Female's voice has more frequency components compared to men.Women speak at one octave higher than men.Even though in the graphs underneath show that a man's voice (while screaming) has a 1 high frequency component ,and than has low intensity after that.Whereas,female's voice has a band of median intensity and gradually tapers towards end.
Spectrograms
Spectrograms are used to show spectral density.It has a horizontal axis of time,a vertical axis showing the frequency and a third axis showing the intensity.For a given spectrogram S, the strength of a given frequency component f at a given time t in the speech signal is represented by the darkness or color of the corresponding point S(t,f).The color red depicts high intensity and yellow, green shows medium intensity and blue hows low intensity ,gray and gradually white depicts that the intensity is under the threshold level.Spectrograms are based on Short Time Fourier Transform(STFT),where the input signal is broken down into blocks and then DFT of each block is take and averaged to find the spectral density.Generally Spectrograms are done in gray scale,where the darkness of a plot represents the high intensity regions.
