Acoustical proximity detection for mobile terminals and other devices

• US 6,542,436 B1
• Filed: 06/30/2000
• Issued: 04/01/2003
• Est. Priority Date: 06/30/2000
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Corporation
• Inventors: Myllyla, Ville
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US09/608,090
• Time in Patent Office: 1,005 Days
• Field of Search: 367/87, 367/95, 367/96, 367/99, 379/422, 379/433, 379/420, 455/569, 455/575
• US Class Current: 367/95
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 15/102 using transmission of pulses having some particular characteristics
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00
• CPC Class Codes: G01S 7/527 Extracting wanted echo signals Doppler systems G01S15/50
• CPC Class Codes: G01S 7/533 Data rate converters
• 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

Abstract

A method and a device for detecting if an object is in proximity to the device, wherein sound (audio) transducers already found in the device are used to realize the proximity detection function, along with digital signal processing or equivalent means. The audio transducers are preferably those designed for use with human hearing and speaking capabilities in the range of about 20 Hz to about 20 kHz, and need not be specially designed transducers. The method includes steps of generating a measurement signal; driving an output acoustic transducer of the device with the measurement signal; monitoring an input acoustic transducer of the device to detect the measurement signal; and determining that an object is in proximity to the device based on a detected alteration of the measurement signal. The device may comprise a mobile telephone, such as a cellular telephone, or a personal communicator. When the device includes a mobile telephone, the step of determining can be used to verify that a handsfree mode of operation can be entered, and/or to set a volume of a signal driving a speaker, and/or to select, modify, or tune an audio processing technique. The step of determining can also be used to automatically enter a handset mode of operation from a handsfree mode of operation. The steps of monitoring and determining include steps of operating plural adaptive filters in parallel on the same input data, with different step sizes, for generating first and second impulse response estimates, respectively, and comparing a difference between the first and second impulse response estimates to a threshold.

Claims

1. A method for detecting if an object is in proximity to a communication device, comprising steps of:

generating a measurement signal;

driving an output acoustic speech transducer of the communications device with the measurement signal, wherein the measurement signal is <

20,000 Hz;

monitoring an input acoustic speech transducer of the communications device to detect the measurement signal; and

determining that an object is in proximity to the communications device based on a detected alteration of the measurement signal.

2. A method as in claim 1, wherein the communications device comprises a mobile telephone.

3. A method as in claim 1, wherein the communications device comprises a personal communicator.

4. A method as in claim 1, wherein the communications device comprises a mobile telephone, and wherein the step of determining is used to verify that a handsfree mode of operation can be entered.

5. A method as in claim 1, wherein the communications device comprises a mobile telephone, and wherein the step of determining is used to set a volume of a signal driving a speaker.

6. A method as in claim 1, wherein the communications device comprises a mobile telephone, and wherein the step of determining is used to select, modify, or tune an audio processing technique.

7. A method as in claim 1, wherein the communications device comprises a mobile telephone, and wherein the step of determining is used to automatically enter a handset mode of operation from a handsfree mode of operation.

8. A method as in claim 1, wherein the steps of monitoring and determining comprise steps of operating plural adaptive filters in parallel on the same input data, with different step sizes, for generating first and second impulse response estimates, respectively, and comparing a difference between the first and second impulse response estimates to a threshold.

9. A communications device comprising an output acoustic speech transducer and an input acoustic speech transducer, said communications device further comprising a unit for detecting if an object is in proximity to the communications device, comprising:

a measurement signal generator for driving said output acoustic speech transducer of said communications device, wherein the measurement signal is <

20,000 Hz;

means for monitoring said input acoustic speech transducer of said communications device to detect the measurement signal; and

means for determining that an object is in proximity to said communications device based on a detected alteration of the measurement signal.

10. A communications device as in claim 9, wherein the communications device comprises a mobile telephone.

11. A communications device as in claim 9, wherein the communications device comprises a personal communicator.

12. A communications device as in claim 9, wherein the communications device comprises a mobile telephone, and wherein said means for determining is used to verify that a handsfree mode of operation can be entered.

13. A communications device as in claim 9, wherein the communications device comprises a mobile telephone, and wherein said means for determining is used to set a volume of a signal driving a speaker.

14. A communications device as in claim 9, wherein the communications device comprises a mobile telephone, and wherein said means for determining is used to select, modify, or tune an audio processing technique.

15. A communications device as in claim 9, wherein the communications device comprises a mobile telephone, and wherein said means for determining is used to automatically enter a handset mode of operation from a handsfree mode of operation.

16. A communications device as in claim 9, wherein said means for monitoring and said means for determining comprise:

a decimator for decimating a measurement signal received from a microphone;

an anti-comb filter for enhancing the signal to noise ratio (SNR) of the received measurement signal;

first and second adaptive filters operated in parallel on the filtered measurement signal, whit different step sizes, for generating first and second impulse response estimates, respectively; and

a comparator for comparing a difference between the first and second impulse response estimates to a threshold.

17. A method for detecting if an object is in proximity to a communications device, comprising steps of:

generating a measurement signal;

over driving an output acoustic speech transducer of the communications device with the measurement signal, wherein the measurement signal is above 16,000 Hz;

monitoring an input acoustic speech transducer of the communications device to detect the measurement signal; and

determining that an object is in proximity to the communications device based on a detected alteration of the measurement signal.