Microphone system for teleconferencing system
First Claim
1. A microphone system for use in a conference environment where an acoustic source emits energy from diverse and varying locations within the environment, comprising:
- at least two directional microphones held in a fixed arrangement about a center point, the respective response of each said microphone being directed radially away from said center point in a different direction, each said microphone able to receive an acoustic signal and produce an electrical signal in response, said microphones comprising two dipole microphones oriented at 90°
from each other;
mixing circuitry to combine said electrical signals in varying proportions to form a composite signal, said composite signal including contributions from at least two of said microphones; and
control circuitry configured to analyze said electrical signals to determine an angular orientation of the acoustic signal relative to said central point, and to substantially continuously adjust said proportions in response to said determined orientation and provide said adjusted proportions to said mixing circuitry,the values of said proportions selected so that said composite signal simulates a signal that would be generated by a virtual directional microphone pivoted about said central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment.
6 Assignments
0 Petitions
Accused Products
Abstract
A microphone system for use in an environment where an acoustic source emits energy from diverse and varying locations within the environment. The microphone system has at least two directional microphones, mixing circuitry, and control circuitry. The microphones are held each directed out from a center point. The mixing circuitry combines the electrical signals from the microphones in varying proportions to form a composite signal, the composite signal including contributions from at least two of the microphones. The control circuitry analyzes the electrical signals to determine an angular orientation of the acoustic signal relative to the central point, and substantially continuously adjusts the proportions in response to the determined orientation and provides the adjusted proportions to the mixing circuitry. The values of the proportions are selected so that the composite signal simulates a signal that would be generated by a single directional microphone pivoted about the central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment.
99 Citations
19 Claims
-
1. A microphone system for use in a conference environment where an acoustic source emits energy from diverse and varying locations within the environment, comprising:
-
at least two directional microphones held in a fixed arrangement about a center point, the respective response of each said microphone being directed radially away from said center point in a different direction, each said microphone able to receive an acoustic signal and produce an electrical signal in response, said microphones comprising two dipole microphones oriented at 90°
from each other;mixing circuitry to combine said electrical signals in varying proportions to form a composite signal, said composite signal including contributions from at least two of said microphones; and control circuitry configured to analyze said electrical signals to determine an angular orientation of the acoustic signal relative to said central point, and to substantially continuously adjust said proportions in response to said determined orientation and provide said adjusted proportions to said mixing circuitry, the values of said proportions selected so that said composite signal simulates a signal that would be generated by a virtual directional microphone pivoted about said central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A microphone system for use in a conference environment where an acoustic source emits energy from diverse and varying locations within the environment, comprising:
-
at least two directional microphones held in a fixed arrangement about a center point, the respective response of each said microphone being directed radially away from said center point in a different direction, each said microphone able to receive an acoustic signal and produce an electrical signal in response; mixing circuitry to combine said electrical signals in varying proportions to form a composite signal, said composite signal including contributions from at least two of said microphones; control circuitry configured to analyze said electrical signals to determine an angular orientation of the acoustic signal relative to said central point, and to substantially continuously adjust said proportions in response to said determined orientation and provide said adjusted proportions to said mixing circuitry, the values of said proportions selected so that said composite signal simulates a signal that would be generated by a virtual directional microphone pivoted about said central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment, and wherein said microphones comprise four cardioid microphones oriented at 90°
to each other. - View Dependent Claims (8)
-
-
9. A microphone system for use in a conference environment where an acoustic source emits energy from diverse and varying locations within the environment, comprising:
-
at least two directional microphones held in a fixed arrangement about a center point, the respective response of each said microphone being directed radially away from said center point in a different direction, each said microphone able to receive an acoustic signal and produce an electrical signal in response; mixing circuitry to combine said electrical signals in varying proportions to form a composite signal, said composite signal including contributions from at least two of said microphones; control circuitry configured to analyze said electrical signals to determine an angular orientation of the acoustic signal relative to said central point, and to substantially continuously adjust said proportions in response to said determined orientation and provide said adjusted proportions to said mixing circuitry, the values of said proportions selected so that said composite signal simulates a signal that would be generated by a virtual directional microphone pivoted about said central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment, and said control circuitry analyzes said electrical signals by a method comprising the steps; blocking each said electrical signal into a sequence of blocks corresponding to time windows of a fixed length, and performing the following steps for each block; computing an energy value for said block; and forming a running peak value, being equal to the block'"'"'s energy value if the block'"'"'s energy value exceeds the running peak value formed for the previous block, and being equal to a decay constant times the previous block'"'"'s running peak value otherwise; having computed a running peak value for a block and for at least two pivotal directions of said virtual directional microphone, comparing the block'"'"'s running peak values for each said direction; and adjusting said proportions so that said mixing circuitry will select during a subsequent block the virtual directional microphone direction whose corresponding running peak value is largest.
-
-
10. A microphone system for use in a conference environment where an acoustic source emits energy from diverse and varying locations within the environment, comprising:
-
at least two directional microphones held in a fixed arrangement about a center point, the respective response of each said microphone being directed radially away from said center point in a different direction, each said microphone able to receive an acoustic signal and produce an electrical signal in response; mixing circuitry to combine said electrical signals in varying proportions to form a composite signal, said composite signal including contributions from at least two of said microphones; control circuitry configured to analyze said electrical signals to determine an angular orientation of the acoustic signal relative to said central point, and to substantially continuously adjust said proportions in response to said determined orientation and provide said adjusted proportions to said mixing circuitry, the values of said proportions selected so that said composite signal simulates a signal that would be generated by a virtual directional microphone pivoted about said central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment, and said proportions are specified by combining and weighting coefficients that maintain the response of said virtual directional microphone at a nearly uniform level, said coefficients being selected from a group whose values being about 1, 0, -1, √
2/2, and -√
2/2.
-
-
11. A method of combining signals from at least two directional microphones in a conference environment with an acoustic source that emits energy from diverse and varying locations within the environment, each said microphone able to receive an acoustic signal and produce an electrical signal in response, the method comprising the steps of:
-
mounting the microphones in a fixed arrangement about a center point, the respective responses of said microphones being directed radially away from said center point in different directions; mixing the electrical signals in varying proportions to form a composite signal, said composite signal including contributions from at least two of said microphones; analyzing said electrical signals to determine an angular orientation of the acoustic signal relative to said central point; substantially continuously selecting and adjusting said proportions in response to said determined orientation and providing said adjusted proportions to said mixing step, the values of said proportions selected so that said composite signal simulates a signal that would be generated by a virtual directional microphone pivoted about said central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment, and the mounting step further comprising either one of the two following steps; providing two dipole microphones and orienting them at 90°
from each other; andproviding four cardioid microphones and orienting them at 90°
to each other; and
the mixing step further comprises forming scaled sums and differences of said electrical signals. - View Dependent Claims (12)
-
-
13. A method of combining signals from at least two directional microphones in a conference environment with an acoustic source that emits energy from diverse and varying locations within the environment, each said microphone able to receive an acoustic signal and produce an electrical signal in response, the method comprising the steps of:
-
mounting the microphones in a fixed arrangement about a center point, the respective responses of said microphones being directed radially away from said center point in different directions; mixing the electrical signals in varying proportions to form a composite signal, said composite signal including contributions from at least two of said microphones; analyzing said electrical signals to determine an angular orientation of the acoustic signal relative to said central point; substantially continuously selecting and adjusting said proportions in response to said determined orientation and providing said adjusted proportions to said mixing step, the values of said proportions selected so that said composite signal simulates a signal that would be generated by a virtual directional microphone pivoted about said central point to direct its maximum response at the acoustic signal as the acoustic signal moves about the environment; blocking each said electrical signal into a sequence of blocks corresponding to time windows of a fixed length, and performing the following steps for each block; computing an energy value for said block; and forming a running peak value, being equal to the block'"'"'s energy value if the block'"'"'s energy value exceeds the running peak value formed for the previous block, and being equal to a decay constant times the previous running peak value otherwise; having computed a running peak value for a block and for at least two pivotal directions of said virtual directional microphone, comparing the block'"'"'s running peak values for each said direction; and adjusting said proportions so that said mixing circuitry will select during a subsequent block the virtual directional microphone direction whose corresponding running peak value is largest.
-
-
14. In a microphone system for use in an environment where an acoustic source moves about the environment, a method comprising the steps of:
-
providing at least two microphones in said environment, each said microphone receiving an acoustic signal from the acoustic source and producing an electrical signal in response thereto; for each said microphone, producing a sequence of samples corresponding to said electrical signal; blocking said samples into blocks of at least one sample each, and performing the following steps for each block; computing an energy value for the samples of said block; and forming a running peak value, the running peak value being equal to the block'"'"'s energy value if the block'"'"'s energy value exceeds the running peak value formed for the previous block, and the running peak value being equal to a decay constant times the previous running peak value otherwise; having computed a running peak value for a block and each microphone, comparing said running peak values for each said microphone; and selecting and preferentially amplifying during a subsequent block the microphone whose corresponding running peak value is largest. - View Dependent Claims (15, 16, 17, 18, 19)
-
Specification