Browse Prior Art Database

Frequency Selection Interlock Circuit

IP.com Disclosure Number: IPCOM000096549D
Original Publication Date: 1963-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Clapper, GL: AUTHOR

Abstract

This circuit provides an interlocking feature in a frequency selective speech recognition system which removes the effects of the sawtooth component from voice waveforms. It allows the resonance components to be correctly discriminated. This filter output control eliminates gross differences between various voices such as occur naturally between speakers and renders the system more uniform in operation.

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Frequency Selection Interlock Circuit

This circuit provides an interlocking feature in a frequency selective speech recognition system which removes the effects of the sawtooth component from voice waveforms. It allows the resonance components to be correctly discriminated. This filter output control eliminates gross differences between various voices such as occur naturally between speakers and renders the system more uniform in operation.

Microphone M supplies the voice frequency inputs through preamplifier PA controlled by an automatic gain control circuit 5. This is in such manner that the output of PA supplies signals of essentially uniform amplitude to the inputs of a plurality of frequency selective filters F1, F2, F3 and SF. The latter is tuned for the sibilant frequencies. The output of each filter is supplied to the base of a transistor clipping amplifier circuit. The collectors are connected to a source of negative potential via collector load resistors. The outputs are taken from the collectors by connections F10, F20, F30 and SF0.

The emitters of each of the clipping amplifiers are commoned. They are connected to the collector of transistor T1 with an integrating circuit comprising resistor R1 and capacitor C1 connected to this common output circuit. The emitter of T1 is connected to a negative potential. The base of T1 is supplied with signals from circuit 5. The signals are selected so that the positive component of the vocal cord transient supplie...