Microphone selection process for use in a multiple microphone voice actuated switching system
First Claim
1. A method of selecting a microphone from a plurality of microphones for transmitting speech signals from said microphone to an output line, the method comprising the steps of:
- measuring a level of speech signals appearing in each of the plurality of microphones responsive to speech sounds, the level of said speech signals in each of the plurality of microphones being determined by a direction of origin for said source of speech sounds;
arranging the plurality of microphones in microphone pairs, a first microphone in each microphone pair having a main beam sensitivity pattern extending in a first direction and a second microphone in each microphone pair having a null pattern extending generally in said first direction;
combining the level of speech signals appearing in said first and second microphones in each one of said microphone pairs for obtaining microphone-pair combination values; and
comparing each microphone-pair combination value for identifying a microphone pair in which said first microphone best receives said speech sounds.
18 Assignments
0 Petitions
Accused Products
Abstract
A microphone selection process is made relatively constant in terms of processing requirements through use of combination values which provide a measure of the quality of the speech signal received in each one of a plurality of microphones. Such combination values are derived in a manner which provides an indication of which one of the plurality of microphones, that provide area coverage for a conference room, for example, best receives the speech signal. In operation, the microphone selection process selects the microphone which best receives the speech signal by comparing a signal energy value received in each one of the microphones to that received in each of the other microphones. More specifically, pairs of microphones are examined, to determine the direction of origin for the speech, by seeking a microphone pair where the speech is strong in the microphone directed toward the source of speech, and weak in an associated microphone directed away from the source of speech. Since a null, which is located at the back of each microphone, is narrower than a main beam or sensitivity pattern, which is located at the front of each microphone, this null is more sensitive to and therefore a better indicator of the direction of origin for the speech than is the main beam. The combination of the signal energy values for each pair of microphones advantageously provides a specific combination value which is used to identify and select the microphone which best receives the speech signal.
-
Citations
32 Claims
-
1. A method of selecting a microphone from a plurality of microphones for transmitting speech signals from said microphone to an output line, the method comprising the steps of:
-
measuring a level of speech signals appearing in each of the plurality of microphones responsive to speech sounds, the level of said speech signals in each of the plurality of microphones being determined by a direction of origin for said source of speech sounds; arranging the plurality of microphones in microphone pairs, a first microphone in each microphone pair having a main beam sensitivity pattern extending in a first direction and a second microphone in each microphone pair having a null pattern extending generally in said first direction; combining the level of speech signals appearing in said first and second microphones in each one of said microphone pairs for obtaining microphone-pair combination values; and comparing each microphone-pair combination value for identifying a microphone pair in which said first microphone best receives said speech sounds. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A voice-actuated switching apparatus for selecting a microphone from a plurality of microphones for transmitting speech signals from said microphone to an output line, the apparatus comprising:
-
means for measuring a level of speech signals appearing in each of the plurality of microphones responsive to speech sounds, the level of said speech signals in each of the plurality of microphones being determined by a direction of origin for said source of speech sounds; means for arranging the plurality of microphones in microphone pairs, a first microphone in each microphone pair having a main beam sensitivity pattern extending in a first direction and a second microphone in each microphone pair having a null pattern extending generally in said first direction; means for combining the level of speech signals appearing in said first and second microphones in each one of said microphone pairs for obtaining microphone-pair combination values; and means for comparing each microphone-pair combination value for identifying a microphone pair in which said first microphone best receives said speech sounds. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
-
29. A voice-actuated switching system comprising:
-
a plurality of circuits for receiving speech sounds and for converting said speech sounds into speech signals; means for measuring a level of said speech signals appearing in each of the plurality of circuits, the level of said speech signals in each of the plurality of circuits being determined by a direction of origin for said source of speech sounds; means for arranging the plurality of circuits into circuit pairs, a first circuit in each circuit pair including means for optimally detecting signals originating in a first direction and a second circuit in each circuit pair including means for optimally detecting signals originating in a second direction, said second direction being generally opposite to said first direction. means for combining the level of speech signals appearing in said first and second circuits in each one of said circuit pairs for obtaining circuit-pair combination values; and means for comparing each circuit-pair combination value for identifying a circuit pair in which said first circuit best receives said speech sounds. - View Dependent Claims (30, 31, 32)
-
Specification