Method for echo cancellation

• US 20020097864A1
• Filed: 01/23/2001
• Published: 07/25/2002
• Est. Priority Date: 01/23/2001
• Status: Abandoned Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Erixon, Mats, Ljungberg, Per
• Application Number:
  US09/767,311
• Publication Number:
  US 20020097864A1
• Time in Patent Office: Days
• US Class Current: 379/406.01
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

A method and apparatus for canceling noise in a communication device is disclosed. Impulse responses to a mechanical non-linear echo in an echo-free environment are measured prior to an initial use of a communication device. A plurality of high energy parameters from these responses are extracted. A mean value of these parameters is computed and pre-stored in non volatile memory of the communication device during production of the device. During an initial use of the communication device, the pre-stored values are downloaded to the static DSP RAM and used to offset the non-linear echo.

Claims

1. A method of offsetting non-linear echo in a communication device having a speaker phone capability, comprising the steps of:

measuring a plurality of impulse responses of the communication device in an anechoic chamber;

extracting a predetermined number of high-energy parameters from the plurality of measurements;

pre-storing said parameters in a non-volatile memory of said communication device.

2. The method of claim 1, wherein said communication device is a mobile telephone.

3. The method of claim 1, wherein said device further comprises an adaptive filter.

4. The method of claim 1, wherein said responses are responses to a mechanical echo from said communication device.

5. The method of claim 1, wherein said pre-stored parameters are downloaded to a non-volatile memory of said communication device upon an initial use of said device.

6. The method of claim 5, wherein said downloaded parameters are used to offset a non-linear echo within said communication device.

7. A communication device, comprising:

an output means for outputting data received by said device;

an input means for receiving input from a user;

an antenna means for enabling said reception and a transmission of said user input; and

a non-volatile memory means for storing a plurality of parameters, wherein said parameters represent impulse responses measured in an anechoic chamber.

8. The device of claim 7, wherein said output means is a speaker.

9. The device of claim 7, wherein said input means is a microphone.

10. The device of claim 7, wherein said responses are responses to a mechanical echo from the communication device.