14. The invention as defined in claim 12 , wherein said calculating means calculates a first self similarity ratio value, corresponding to a first sample delay, as a first periodicity characteristic value; and said determining means determines that said input signal segment is voice-band data if said first self similarity ratio value is greater than a first similarity threshold.
14. The invention as defined in claim 12 , wherein said calculating means calculates a first self similarity ratio value, corresponding to a first sample delay, as a first periodicity characteristic value; and said determining means determines that said input signal segment is voice-band data if said first self similarity ratio value is greater than a first similarity threshold. 15. The invention as defined in claim 14 , wherein said calculating means calculates a second self similarity ratio value, corresponding to a second sample delay, as a second periodicity characteristic value, said second sample delay being greater than said first sample delay; and said determining means determines that said input signal segment is speech if said second self similarity ratio value is greater than a second similarity threshold.