MICROPHONE PROXIMITY DETECTION

• US 20100080084A1
• Filed: 09/30/2008
• Published: 04/01/2010
• Est. Priority Date: 09/30/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Lee, Jae, Pope, Benjamin John, Dinh, Richard Hung Minh, Chen, Shaohai, Seguin, Chad G.
• Granted Patent: US 8,189,429 B2
• Time in Patent Office: Days
• US Class Current: 367/118
• CPC Class Codes: G01S 11/14 using ultrasonic, sonic, or infrasonic waves
• CPC Class Codes: H04M 1/03 Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets
• CPC Class Codes: H04M 1/6008 in the transmitter circuit
• CPC Class Codes: H04M 1/605 involving control of the receiver volume to provide a dual operational mode at close or far distance from the user
• CPC Class Codes: H04M 2250/22 including a touch pad, a touch sensor or a touch detector digitizers for touch screens G06F3/041
• CPC Class Codes: H04W 8/22 Processing or transfer of terminal data, e.g. status or physical capabilities

Abstract

A mobile communications device contains at least two microphones. One microphone is located away from the handset receiver and serves to pick up voice of a near end user of the device for transmission to the other party during a call. Another microphone is located near the handset receiver and serves to pick up acoustic output of the handset receiver (a far end signal). A signal processor measures the frequency response of the receiver. The signal processor performs spectral analysis of the receiver frequency response to determine whether or not the device is being held at the ear of the user. On that basis, the device automatically changes its operating mode, e.g., turns on or off a touch sensitive display screen during the call. Other embodiments are also described.

Claims

1. An apparatus comprising:

a mobile communications device housing having integrated therein;

a downlink channel processor to receive an incoming signal from a far end user;

a receiver or earpiece speaker coupled to an output of the downlink channel processor to receive the incoming signal from the far end user and to output a receiver acoustic signal;

a first microphone located far from the receiver to pick up voice of a near end user and to output a voice signal of the near end user;

an uplink channel processor to send the voice signal of the near end user to the far end user;

a second microphone located near the receiver to pick up the receiver acoustic signal and to output an audio signal representing the receiver acoustic signal; and

a signal processor to measure a frequency response which is a function of (a) the audio signal representing the receiver acoustic signal and (b) the incoming signal from the far end user, the signal processor to analyze the frequency response to detect a proximity of the apparatus to an object.

2. The apparatus of claim 1, wherein the signal processor is to determine whether the apparatus is situated in one of an at-ear position or an open position, based on the proximity of the apparatus to the object.

3. The apparatus of claim 1, wherein the mobile communications device housing has a handset receiver opening at which the second microphone and the receiver are situated.

4. The apparatus of claim 1, wherein when the proximity of the apparatus to the object is near, the frequency response over a frequency band is of greater magnitude than when the proximity of the apparatus to the object is far.

5. The apparatus of claim 4, wherein the frequency band is in the range of less than 1000 Hz.

6. The apparatus of claim 4, wherein the apparatus is to automatically switch from a handset mode to a speaker mode during a telephone call in response to the magnitude of the frequency response dropping below a threshold value.

7. The apparatus of claim 1, wherein the frequency response is a ratio of H_out/H_in as a function of frequency, wherein H_out corresponds to the audio signal and H_in corresponds to the incoming signal.

8. An apparatus comprising:

a mobile communications device housing having integrated therein;

a downlink channel processor to receive an incoming signal from a far end user;

a speakerphone speaker coupled to an output of the downlink channel processor to receive the incoming signal from the far end user and to output a speakerphone acoustic signal;

a first microphone to pick up voice of a near end user and to output a voice signal of the near end user;

an uplink channel processor to send the voice signal of the near end user to the far end user;

a second microphone to pick up the speakerphone acoustic signal and to output an audio signal; and

a signal processor to measure a time domain level of the audio signal to detect a proximity of the apparatus to an object.

9. The apparatus of claim 8, further comprising:

a touch sensitive display screen; and

a proximity detector to measure proximity of the display screen to the object, the proximity detector to enhance accuracy of a measure of final proximity based on the proximity detected by the signal processor.

10. The apparatus of claim 9, wherein the proximity detector is to determine whether the apparatus is situated in one of an at-ear position or an open position, and wherein the apparatus is to automatically disable call handling input through the touch sensitive display screen during the call in response to the apparatus being situated in the at-ear position.

11. The apparatus of claim 8, wherein the apparatus is to automatically switch from a speaker mode to a handset mode during a telephone call based on the measure of the time domain level of the audio signal.

12. A method for operating a mobile telephony device, comprising:

monitoring during a call a frequency response of a handset receiver of the mobile device over a frequency band;

maintaining the mobile device in one operating mode, while the frequency response over the frequency band is on one side of a predetermined threshold value; and

switching the mobile device from said one operating mode to a different operating mode automatically, when the frequency response over the frequency band goes to another side of the predetermined threshold value.

13. The method of claim 12, wherein the frequency band is in the range of less than 1000 Hz.

14. The method of claim 13, wherein the frequency response is a ratio of H_out/H_in as a function of frequency, wherein H_out corresponds to output from the handset receiver as detected by a microphone that is integrated with the handset receiver, and H_in corresponds to input to the handset receiver.

15. The method of claim 12, wherein in said one operating mode a touch screen of the device is activated to enable user input, and in some different operating mode the touch screen is inactive to disable user input.

16. A machine-implemented method comprising:

measuring acoustic output of a speakerphone speaker in a mobile device during a call;

determining a proximity of an object to the mobile device based on the measured acoustic output;

maintaining speakerphone mode of the mobile device during the call when the proximity indicates far; and

switching the mobile device from the speakerphone mode to handset mode automatically when the proximity indicates near.

17. The method of claim 16, wherein user input through a touch sensitive display screen of the device is suppressed in the handset mode and enabled in the speaker phone mode.

18. The method of claim 16, wherein the proximity indicates near when the mobile device is situated in an at-ear position and far when the mobile device is situated in an open position.

19. The method of claim 16, further comprising:

reading a proximity sensor, wherein said determining the proximity is further based on said reading.

20. The method of claim 16, wherein said switching the mobile device comprises turning off a touch sensitive display screen of the device in the handset mode, and turning on the touch sensitive display screen of the device in the speakerphone mode.