Echo suppression for wireless handsets and headsets
The enhancements provided herein are designed to allow an acoustic echo suppressor algorithm to operate with significant echo path delay between an audio block R in and audio block S in . In one illustration, a single reference sample or envelope value can be taken from the received audio block R in . Through an algorithm, echo signals can be suppressed and/or masked from audio block S in by delaying the previously captured reference sample and aligning the delayed reference sample with multiple samples of the audio block S in . Instead of each individual reference sample being matched with an individual sample of the audio block S in , a single captured and delayed reference sample or envelope value can be matched with multiple samples of audio block S in . The algorithm presented improves voice quality on a telephone call while reducing buffer requirements.
1 . A method for suppressing echo signals generated between a speaker and a microphone having echo path delay on at least one of a wireless handset and headset comprising:
capturing a reference sample from an audio block provided to said speaker; and
delaying and aligning said reference sample with multiple samples of an audio block received through said microphone.
2 . The method of claim 1 , wherein capturing said reference sample comprises using raw data of said audio block provided to said speaker.
3 . The method of claim 1 , wherein capturing said reference sample comprises using an envelope calculation of said audio block provided to said speaker.
4 . The method of claim 1 , wherein capturing said reference sample comprises using approximately a one millisecond interval from said audio block provided to said speaker.
5 . The method of claim 1 , wherein capturing said reference sample comprises taking said reference sample from multiple samples contained in said audio block provided to said speaker.
6 . The method of claim 5 , wherein taking said reference sample from said multiple samples comprises using a first sample within said multiple samples contained in said audio block provided to said speaker.
7 . The method of claim 5 , wherein taking said reference sample from said multiple samples comprises using a last sample within said multiple samples contained in said audio block provided to said speaker.
8 . The method of claim 1 , comprising sampling audio blocks provided to said speaker and received through said microphone at different frequencies.
9 . The method of claim 8 , wherein sampling said audio blocks provided to said speaker and received through said microphone comprises using eight kilohertz narrowband.
10 . The method of claim 8 , wherein sampling said audio blocks provided to said speaker and received through said microphone comprises using sixteen kilohertz wideband.
11 . The method of claim 1 , comprising temporarily storing said reference sample.
12 . An apparatus for at least one of a wireless handset and headset comprising:
at least one processor; and
a memory operatively coupled to said processor, said memory storing program instructions that when executed by said processor, causes said processor to:
determine a reference sample;
suppress echoes from an audio block by delaying said reference sample and aligning said reference sample with multiple samples of said audio block.
13 . The apparatus of claim 12 , wherein said reference sample is delayed by approximately sixty to sixty-five milliseconds.
14 . The apparatus of claim 13 , wherein said delay is for a Bluetooth™ wireless connection.
15 . The apparatus of claim 14 , wherein delaying said reference sample comprises accounting for time introduced by at least one of an analog-to-digital converter, digital-to-analog converter and a digital coder-decoder.
16 . A system comprising:
acoustic echo suppressor logic for generating a reference sample and masking echo signals from audio by delaying said reference sample by a period of time and aligning said reference sample with multiple samples of said audio.
17 . The system of claim 16 , wherein said period of time takes into account of delays introduced by at least one of a wireless headset and handset.
18 . The system of claim 17 , wherein said reference sample is taken from an audio block provided to said at least one of a wireless headset and handset.
19 . The system of claim 16 , wherein said audio is sampled using eight kilohertz narrowband.
20 . The system of claim 16 , wherein said audio is sampled using sixteen kilohertz wideband.