# US 8,542,843 B2 · Headset with integrated stereo array microphone

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- Number: US 8,542,843 B2
- Document ID: US8542843B2
- Status: Granted
- Kind: B2
- Application number: 12/429,623
- Filed: 2009-04-24
- Published: 2009-10-29
- Granted: 2013-09-24
- Earliest claimed: 2008-04-25
- Assignees: Andrea Electronics Corporation
- Applicants: Douglas Andrea; Qunsheng Liu; John Probst
- Inventors: Douglas Andrea; Qunsheng Liu; John Probst
- Web page: https://patentgrep.com/patent/US8542843B2

## CPC

- H04R 3/005: {for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407)}
- H04R 5/033: Headphones for stereophonic communication {(details thereof, e.g. relating to batteries, cables or control elements H04R1/10)}
- H04R 2201/107: Monophonic and stereophonic headphones with microphone for two-way hands free communication
- H04R 2430/20: Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic (H04R2203/12 takes precedence)
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

The invention relates to a noise canceling audio transmitting/receiving device; a stereo headset with an integrated array of microphones utilizing an adaptive beam forming algorithm. The invention also relates to a method of using an adaptive beam forming algorithm that may be incorporated into a stereo headset. The sensor array used herein has adaptive filtering capabilities.

## Claims

### Claim 1

A noise canceling audio transmitting/receiving device, said device comprising:
at least one audio outputting means; and
at least one audio receiving means, each for receiving an acoustic signal and outputting an electrical signal representing the received acoustic signal;
wherein each of said receiving means is directly mounted on a surface of a corresponding outputting means; and
processing means connected to the audio receiving means and operable to apply a frequency domain adaptive filter to the electrical signal output by the audio receiving means, said processing means operable to carry out processing comprising:
applying an averaging filter on the digitized electrical signal output by each of the receiving means,
continuously calculating a beam, a beam reference, a reference average, and noise estimation based on the output of the averaging filter to continuously update filter coefficients of the adaptive filter, and
selectively applying the adaptive filter to the output of the averaging filter.

### Claim 2 (depends on 1)

The device according to claim 1, wherein said noise canceling audio transmitting/receiving device is a stereo headset.

### Claim 3 (depends on 2)

The device according to claim 2, wherein said at least one audio outputting means is a speaker, headphone, or an earphone.

### Claim 4 (depends on 2)

The device according to claim 2, wherein said at least one audio receiving means is a microphone.

### Claim 5 (depends on 4)

The device according to claim 4, wherein said microphone is a uni or omni-directional electret microphone, or a microelectromechanical systems (MEMS) microphone.

### Claim 6 (depends on 1)

The device according to claim 1, wherein said noise canceling audio transmitting/receiving device further comprises a connecting means to connect to a computing device or an external device.

### Claim 7 (depends on 6)

The device according to claim 6, wherein said noise canceling audio transmitting/receiving device can be connected to said computing device or said external device via a stereo speaker/microphone input or Bluetooth® or a USB external sound card device.

### Claim 8 (depends on 1)

The device according to claim 1, wherein a position of said at least one audio receiving means is adjustable with respect to a user's mouth.

### Claim 9 (depends on 1)

The device according to claim 1, wherein the audio receiving means comprises at least two audio receiving means.

### Claim 10 (depends on 1)

The device according to claim 1, wherein each of at least two audio receiving means corresponds to a separate channel.

### Claim 11 (depends on 10)

The device according claim 10, where a first one of said separate channels is a left channel and a second one of said separate channels is a right channel.

### Claim 12 (depends on 10)

The device according to claim 10, wherein said processing performed by said processing means is performed for each separate channel.

### Claim 13 (depends on 12)

The device according to claim 12, wherein said processing means further calculates a beam average representing an average of beams representing each of representing the acoustic signals on each of said separate channels, wherein said beam average is compared against threshold value and said filter coefficients are adjusted if said beam average is below said threshold.

### Claim 14 (depends on 1)

The device according to claim 1, wherein the beam reference is an in-phase beam reference.

### Claim 15

A noise canceling audio transmitting/receiving device, said device comprising:
at least one audio outputting means; and
at least one audio receiving means, each for receiving an acoustic signal and outputting an electrical signal representing the received acoustic signal;
wherein each of the at least one audio receiving means is directly mounted on a surface of a corresponding outputting means; and
processing means connected to the audio receiving means and configured to convert the electrical signal representing the received acoustic signal to a frequency domain signal, said processing means further configured to carry out processing comprising:
applying an averaging filter to the frequency domain signal by each of the at least one audio receiving means,
repeatedly calculating a beam, a beam reference, a reference average, and noise estimation based on the output of the averaging filter to repeatedly update filter coefficients of a frequency domain adaptive filter, and
applying the frequency domain adaptive filter to the output of the averaging filter; and
calculating an error by subtracting the beam from a beam average, wherein calculating the noise estimation is further based on the error.

### Claim 16 (depends on 15)

The device according to claim 15, wherein the beam average comprises an average of all previously calculated beams.

### Claim 17

A noise canceling audio transmitting/receiving device, said device comprising:
at least one speaker; and
at least two microphones each located a predetermined distance from an acoustic source and configured to output an electrical signal on a respective channel;
wherein each of the at least two microphones is mounted on a surface of a corresponding speaker; and
a signal processor configured to receive from the microphones the electrical signals on each respective channel and to convert the time domain electrical signals to frequency domain electrical signals, said signal processor configured to apply an averaging filter to the frequency domain electrical signals, the signal processor further configured to calculate current filter coefficients for a beam representing the acoustic signal for application in said frequency domain adaptive filter, and to calculate a beam reference, a reference average, and a noise estimation based on output of the averaging filter to update filter coefficients of a frequency domain adaptive filter, and to apply the frequency domain adaptive filter to the output of the averaging filter;
wherein the signal processor is further configured to calculate an error by subtracting the beam from a beam average, wherein calculating the noise estimation is further based on the error.

### Claim 18 (depends on 17)

The device according to claim 17, wherein the beam average comprises an average of all previously calculated beams.

### Claim 19 (depends on 17)

The device according to claim 17, wherein each of said microphones is a highly directional microphone.

### Claim 20 (depends on 17)

The device according to claim 17, wherein a position of each of said microphones is adjustable with respect the acoustic source.
