Abstract: A device for shielding aircraft avionics and other electronic equipment from electromagnetic radiation generated by electronic devices used aboard the aircraft. The device includes a contiguous conductive shield which can be of wire mesh and which partially or completely surrounds a compartment or compartments of the aircraft, such as the passenger compartment and cargo compartments, and absorbs and dissipates the electromagnetic radiation which originates in the compartment from the electronic devices. The aircraft windows are also shielded with the conductive shield or, alternatively, may be coated with a transparent thin conductive polymer to allow better viewing.

Abstract: An apparatus for receiving spoken input training words and for subsequently recognizing a spoken input command word. For each training word, and for the command word, there is stored a time dependent array and a cumulative feature non-time-dependent vector. The command word array is compared, member-by-member, with each training word array. Also, the command word vector is compared, feature-by-feature, with each training word vector. The results of both comparisons are used for selecting the training word which most closely matches the command word.

Abstract: A speech recognition technique is disclosed for recognizing words that are spoken at speeds that approach the speed of continuous speech.To avoid the cost of a rigorous approach wherein all possible words of stored vocabulary are correlated against each group of speech samples, this invention uses relatively long duration inter-string pauses to detect string boundaries, and relatively short duration inter-segment pauses to determine speech segment boundaries which are used as a limited number of start or end points.

Abstract: In this speech recognition system the array formed by a timewise sequence of speech signal feature vectors includes digital data at each time slot representing both presence/absence and consistency of occurence.

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 which receives spoken input training words and a subsequent spoken input command word and generates a correlation function is indicative of the resemblance of the command word to each training word. A feature extraction means processes received input words and generates digital feature output signals on particular ones of a number of feature output lines. Means are provided for storing, as a time dependent matrix, the status of the feature signals which occur during each training word. Means are also provided for storing as a time dependent matrix, the status of the feature signals which occur during the command word. Further means are provided for comparing, member by member, the command word matrix with each training word matrix and for generating a correlation figure which reflects each comparison. In a preferred embodiment of the invention, means are provided for time normalizing the matrices representative of the training words and the command word before the comparisons are made.

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.

Abstract: The present invention pertains to an apparatus which receives acoustic input, the input including words spoken in isolation, finds the word boundary instants at which a word begins and ends, and performs recognition functions on the words. A feature of the invention is the compensation for breath noise after the true end of a word, using a variable backup of the estimated word end. The apparatus includes means for generating feature signals indicative of feature characteristics in the received input and further includes means for comparing the feature signals which occurred during determined time boundaries with stored features corresponding to words in a vocabulary. The invention is directed to an improved system for detecting word boundaries which includes a means responsive to the input for generating a first feature signal indicative of the substantially continuing presence of speech-like sounds which meet a first selection criterion.

Abstract: An apparatus and method for recognizing the occurrence of a command word from among input speech that may be continuous in form. In accordance with the invention, means are provided for generating feature signals which depend on the features of an input word being spoken. The feature signals are processed to determine the time interval of occurrence of a predetermined sequence of features. Also provided is a means for comparing the feature signals which occur during the determined time interval with a stored set of features that are expected to occur characteristically during the command word to determine the degree of correlation therebetween.