Cepstrum provides a compact representation of the vocal tract system information.

The vocal tract system information is characterized by the spectral envelope. This slow varying component in the spectrum is characterized by the first few coefficients in the cepstral domain. Note that cepstrum computation can be interpreted as the spectral analysis of a signal which is the log-magnitude spectrum in this case.

Note that the pitch period of a voiced segment of speech can be measured from the cepstrum.