12. An apparatus for discriminating speech from voice-band data in a communication network, comprising: calculating means for calculating a self similarity ratio value, representing a periodicity characteristic, and an autocorrelation coefficient value, representing a spectral characteristic, for an input signal segment, wherein calculating the self similarity ratio value includes calculating a plurality of different self similarity ratio values and selecting the highest one of the plurality of different self similarity ratio values as the calculated self similarity ratio value; and determining means for determining whether said input signal segment is speech or voice-band data based on said at least one of said self similarity value and said autocorrelation coefficient value.
12. An apparatus for discriminating speech from voice-band data in a communication network, comprising: calculating means for calculating a self similarity ratio value, representing a periodicity characteristic, and an autocorrelation coefficient value, representing a spectral characteristic, for an input signal segment, wherein calculating the self similarity ratio value includes calculating a plurality of different self similarity ratio values and selecting the highest one of the plurality of different self similarity ratio values as the calculated self similarity ratio value; and determining means for determining whether said input signal segment is speech or voice-band data based on said at least one of said self similarity value and said autocorrelation coefficient value. 13. The invention as defined in claim 12 , wherein said input signal segment is a frame of N samples.