Speech analyzing system

Abstract

Abstract 1,236,431. Speech analysis. INTERNATIONAL BUSINESS-MACHINES CORP. 27 Aug., 1968 [7 Sept., 1967], No. 40821/68. Heading G4R. Sound analysing apparatus comprises a plurality of devices for detecting respective sound characteristics, means for scanning the devices in cycles, and storage means, the outputs of the devices being stored in the storage means under control of a system receiving an exponential timing signal. A speech signal is split by a preamplifier into high, middle and low frequency bands which go to a fricative selector, harmonic locator and envelope peak detector respectively. The envelope peak detector provides an automatic gain control voltage for the preamplifier, and detects the fundamental to start a scan ring and a timing ring. The scan ring enables ten cup-andbucket scan counters in turn to count pulses from the harmonic locator. The outputs of the fricative selector and scan counters are fed to interlocked balance units which compare them in pairs (adjacent) to detect formants. Adjacent outputs of the balance units are combined in pairs in and-invert units, the parallel outputs of which are entered into a column of a storage matrix, successive columns being selected in turn for this by the timing ring. The matrix contents are displayed on lamps. A fricative (or sibilant) sound can also start the timing ring but advance by more than one step is inhibited until the fricative has ended. Similarly, if the fricative occurs in the middle of a speech signal, so that the timing ring is already advancing, this advance is inhibited until the fricative has ended. An exponentially-falling voltage is used to control a multivibrator which drives the timing ring so that the intervals between successive steps of the ring increase exponentially. A fricative (or sibilant) sound resets the exponential voltage to its highest value so that following storing of the fracitive (consonant) characteristics in the matrix subsequent fine (vowel) details are also stored by virtue of the intial relatively short intervals between steps of the timing ring.

Inventors

• 👤 Genung L Clapper

Bibliographic Details