B. Yegnanarayana et al., AN ITERATIVE ALGORITHM FOR DECOMPOSITION OF SPEECH SIGNALS INTO PERIODIC AND APERIODIC COMPONENTS, IEEE transactions on speech and audio processing, 6(1), 1998, pp. 1-11
The speech signal may be considered as the output of a time-varying vo
cal tract system excited with quasiperiodic and/or random sequences of
pulses, The quasiperiodic part may be considered as the deterministic
or periodic component and the random part as the stochastic or aperio
dic component of the excitation, In this paper, we discuss issues invo
lved in identifying and separating the periodic and aperiodic componen
ts of the source. The decomposition is performed on an approximation t
o the excitation signal, instead of decomposing the speech signal dire
ctly, The linear prediction residual signal is used as an approximatio
n to the excitation signal of the vocal tract system, Speech is first
analyzed to determine the voiced and unvoiced parts of the signal, Dec
omposition of the voiced part into periodic and aperiodic components i
s then accomplished by first identifying the frequency regions of harm
onic and noise components in the spectral domain, The signal correspon
ding to the noise regions is used as a first approximation to the aper
iodic component, An iterative algorithm is proposed which reconstructs
the aperiodic component in the harmonic regions. The periodic compone
nt is obtained by subtracting the reconstructed aperiodic component si
gnal from the residual signal, The individual components of the residu
al are then used to excite the derived all-pole model of the vocal tra
ct system to obtain the corresponding components of the speech signal,
Experiments were conducted using synthetic speech, They demonstrated
the ability of the algorithm for decomposition of a synthetic speech s
ignal made of a mixture of periodic and aperiodic components, Applicat
ion to natural speech is also discussed.