Audibility enhancement

• US 20050004796A1
• Filed: 02/25/2004
• Published: 01/06/2005
• Est. Priority Date: 02/27/2003
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Trump, Tonu, Eriksson, Anders
• Granted Patent: US 7,092,514 B2
• Time in Patent Office: Days
• US Class Current: 704/225
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H04M 1/6016 in the receiver circuit
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones
• CPC Class Codes: H04M 9/08 Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic

Abstract

An apparatus for enhancing audibility of a far-end speech signal from a far-end user to a near-end user in a telephony system includes a near-end background noise signal level estimator (26) at the near-end user. A near-end speech signal level estimator (24) is also provided at the near-end user. A gain control logic (22) determines a gain (G) for amplification of the far-end speech signal based on both estimated speech and background noise signal levels.

Claims

1. A method of enhancing audibility of a far-end signal from a far-end user to a near-end user in a telephone system, including the steps of

determining a gain as a function varying in both in an estimated near-end background noise signal level and an estimated near-end speech signal level;

and

applying said gain to said far-end speech signal.

2. The method of claim 1, including the steps of

determining a first threshold from an estimated maximum far-end speech signal level;

limiting said gain to values below said first threshold.

3. The method of claim 1, including the steps of

determining a second threshold from at least one estimated echo return loss;

limiting said gain to values below said second threshold.

4. The method of claim 1, including the steps of

determining a first threshold from an estimated maximum far-end speech signal level;

determining a second threshold from at least one estimated echo return loss;

limiting said gain to values below the smallest of said first and second thresholds.

5. The method of claim 1, including the step of low pass filtering said determined gain before application to said far-end speech signal.

6. An apparatus for enhancing audibility of a far-end speech signal from a far-end user to a near-end user in a telephone system, including

gain control logic for determining a gain as a function varying in both an estimated near-end background noise signal level and an estimated near-end speech signal level;

and

an amplifier for applying said gain to said far-end speech signal.

7. The apparatus of claim 6, including

means for determining a first threshold from an estimated maximum far-end speech signal level,

means for limiting said gain to values below said first threshold.

8. The apparatus of claim 6, including

means for determining a second threshold from at least one estimated echo return loss;

means for limiting said gain to values below said second threshold.

9. The apparatus of claim 6, including

means for determining a first threshold from an estimated maximum far-end speech signal level;

means for determining a second threshold from at least one estimated echo return loss;

means for limiting said gain to values below the smallest of said first and second thresholds.

10. The apparatus of claim 6, including a low pass filter for filtering said determined gain before application to said far-end speech signal.