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US 2014/0112466 A1Published application
System and Method for Clock Synchronization of Acoustic Echo Canceller (AEC) with Different Sampling Clocks for Speakers and Microphones
AssigneeCisco Technology, Inc.
InventorsFeng Bao, J. William Mauchly, Subrahmanyam Kunapuli, Xiangyu Bao
Life of this patent
Estimating the term…
Abstract
Clock synchronization for an acoustic echo canceller (AEC) with a speaker and a microphone connected over a digital link may be provided. A clock difference may be estimated by analyzing the speaker signal and the microphone signal in the digital domain. The clock synchronization may be combined in both hardware and software. This synchronization may be performed in two stages, first with coarse synchronization in hardware, then fine synchronization in software with, for example, a re-sampler.
Claims29
A method comprising:
- determining a coarse frequency difference between a first clock and a second clock;
- performing a coarse frequency adjustment of at least one of the following:
- the first clock and the second clock to reduce the determined coarse frequency difference;
- determining, in response to performing the coarse frequency adjustment, a fine frequency difference between the first clock and the second clock;
- and
- performing a fine frequency adjustment to reduce the determined fine frequency difference.
3 more elements
An apparatus comprising:
- a speaker portion having a first clock;
- a digital link;
- and
- a microphone portion having a second clock and being connected to the speaker portion over the digital link, the microphone portion comprising an acoustic echo canceller configured to;
- determine a coarse frequency difference between the first clock and the second clock,
- perform a coarse frequency adjustment of at least one of the following:
- the first clock and the second clock to reduce the determined coarse frequency difference,
- determine, in response to performing the coarse frequency adjustment, a fine frequency difference between the first clock and the second clock, and
- perform a fine frequency adjustment to reduce the determined fine frequency difference.
6 more elements
An apparatus comprising:
- a microphone portion having a first clock;
- a digital link;
- and
- a speaker portion having a second clock and being connected to the microphone portion over the digital link, the speaker portion comprising an acoustic echo canceller configured to;
- determine a coarse frequency difference between the first clock and the second clock,
- perform a coarse frequency adjustment of at least one of the following:
- the first clock and the second clock to reduce the determined coarse frequency difference,
- determine, in response to performing the coarse frequency adjustment, a fine frequency difference between the first clock and the second clock, and
- perform a fine frequency adjustment to reduce the determined fine frequency difference.
6 more elements
Dependencies are inferred from the claim text.