Abstract: An apparatus for recognizing the occurrence of a command word within continuous speech, features an improved sequential processing of feature signals derived from the input speech: feature subsets are compared with previously stored subset signals to determine the time interval or boundary of command word candidates. The occurrence decision and indication of the command word is made from a comparison of a feature signal matrix versus a previously stored training matrix.

Abstract: An apparatus for signal-in-noise enhancement by useful-channel selection, includes automatic channel switching if words of a predetermined speech vocabulary are not detected within a predetermined interval. In accordance with the invention there are provided first and second parallel channels to which audio signals are applied. A channel selector, such as a voltage controlled switch, is responsive to a control signal for selecting the first or the second channel. A speech word recognition subsystem is provided and is responsive to the audio signals transmitted over the selected channel. The speech recognition subsystem determines the presence of speech-like sounds and generates a speech-indicative signal as a function thereof.