Tone detector judging a detection of a predetermined tone signal by comparing a characteristic quantity of the tone signal with characteristic quantities of other signals

摘要

A tone transmission part transmits a tone signal. A tone signal detection part detects data representing an echo signal of the tone signal transmitted by the tone transmission part, and detects data representing a predetermined tone signal targeted to be detected. The tone signal detection part also detects data representing tone signals of all of input signals. A tone judgment part excludes the data representing the echo signal from the data representing the tone signals of all of the input signals so as to judge a detection of the predetermined tone signal.