Ming Zhang

US Patent:

6920111, Jul 19, 2005

Filed:

Mar 21, 2003

Appl. No.:

10/394941

Inventors:

Ming Zhang - San Jose CA, US
Yung-Chin Chen - San Jose CA, US
Abhijit Warkhedi - San Jose CA, US

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04J001/16

US Classification:

370235, 370392, 370401, 370413, 709226, 709249

Abstract:

Methods and devices for controlling traffic in a multi-level system are described. A first counter associated with a first node in a first level of the system is incremented. A second counter associated with a second node in an upstream level of the system is incremented. The first counter is incremented more frequently than the second counter.

US Patent:

7003099, Feb 21, 2006

Filed:

Feb 21, 2003

Appl. No.:

10/371150

Inventors:

Ming Zhang - Cupertino CA, US

Assignee:

Fortmedia, Inc. - Cupertino CA

International Classification:

H04B 3/23
H04B 15/02

US Classification:

37940603, 37940605, 37939201, 37938802, 381 943

Abstract:

Techniques for canceling echo and suppressing noise using an array microphone and signal processing. In one system, at least two microphones form an array microphone and provide at least two microphone input signals. Each input signal may be processed by an echo canceller unit to provide a corresponding intermediate signal having some echo removed. An echo cancellation control unit receives the intermediate signals and derives a first gain used for echo cancellation. A noise suppression control unit provides at least one control signal used for noise suppression based on background noise detected in the intermediate signals. An echo cancellation and noise suppression unit derives a second gain based on the control signal(s), cancels echo in a designated intermediate signal based on the first gain, and suppresses noise in this intermediate signal based on the second gain. The signal processing may be performed in the frequency domain.

US Patent:

7174022, Feb 6, 2007

Filed:

Jun 20, 2003

Appl. No.:

10/601055

Inventors:

Ming Zhang - Cupertino CA, US
Kuoyu Lin - San Jose CA, US

Assignee:

ForteMedia, Inc. - Cupertino CA

International Classification:

H04R 3/00

US Classification:

381 92, 381 942, 381 943, 704226

Abstract:

Techniques are provided to suppress noise and interference using an array microphone and a combination of time-domain and frequency-domain signal processing. In one design, a noise suppression system includes an array microphone, at least one voice activity detector (VAD), a reference generator, a beam-former, and a multi-channel noise suppressor. The array microphone includes multiple microphones—at least one omni-directional microphone and at least one uni-directional microphone. Each microphone provides a respective received signal. The VAD provides at least one voice detection signal used to control the operation of the reference generator, beam-former, and noise suppressor. The reference generator provides a reference signal based on a first set of received signals and having desired voice signal suppressed. The beam-former provides a beam-formed signal based on a second set of received signals and having noise and interference suppressed. The noise suppressor further suppresses noise and interference in the beam-formed signal.

US Patent:

7177416, Feb 13, 2007

Filed:

Jul 10, 2002

Appl. No.:

10/193689

Inventors:

Ming Zhang - Cupertino CA, US
KuoYu Lin - San Jose CA, US

Assignee:

ForteMedia, Inc. - Cupertino CA

International Classification:

H04M 9/08

US Classification:

37938701, 37940605

Abstract:

An acoustic echo canceller comprising an adaptive filter, a post filter, and an adjustable filter. The adaptive filter receives a reference signal and a near-end signal, cancels a portion of the echo in the near-end signal using the reference signal, and provides an intermediate signal having remaining echo not canceled by the adaptive filter. The post filter calculates the cross-correlation between the near-end signal and intermediate signal, and provides a set of coefficients based on a variable suppression parameter. The adjustable filter processes the intermediate signal based on the coefficients and provides an output signal having at least a portion of the remaining echo removed. The acoustic echo canceller may further comprise a channel control unit that provides control signals, an adjustable amplifier, a noise estimator that estimates the noise in the intermediate signal, and a noise reinsertion unit that reinserts a version of the estimated noise back into the output signal.

US Patent:

7333605, Feb 19, 2008

Filed:

Jul 10, 2002

Appl. No.:

10/193739

Inventors:

Ming Zhang - Cupertino CA, US
Kuoyu Lin - San Jose CA, US

Assignee:

Fortemedia, Inc. - Cupertino CA

International Classification:

H04M 9/08

US Classification:

37940608, 370286

Abstract:

An acoustic echo canceller having an adaptive filter, a step size control unit, and (optionally) a stability control unit. The adaptive filter derives an estimate of the echo in a near-end signal using a digital filter (e. g. , a FIR filter) and further cancels the echo estimate from the near-end signal to provide an output signal. The step size control unit derives step sizes to be used to adjust the coefficients of the digital filter. The step sizes are determined based on the characteristics of a reference signal and the output signal and (optionally) the characteristics of the coefficients. For example, the step size is set proportional to the reference signal amplitude, inversely proportional to the output signal amplitude, and based on a difference in the coefficient power at two different time instants. The stability control unit constrains the adjustments to the coefficients to prevent instability.

US Patent:

7373572, May 13, 2008

Filed:

May 12, 2005

Appl. No.:

11/128692

Inventors:

Tak M. Mak - Union City CA, US
Ming Zhang - Urbana IL, US
Subhasish Mitra - Folsom CA, US
Paul E. Shipley - Sunnyvale CA, US

Assignee:

Intel Corporation - Santa Clara CA

International Classification:

G01R 31/28

US Classification:

714729, 714724, 714799, 714819, 714 6, 327202, 377 70

Abstract:

In one embodiment, an apparatus includes a system pulse latch to generate at least one system latch signal in response to a data input signal and a pulsed system clock signal; a shadow pulse latch to generate at least one shadow latch signal in response to the data input signal and the pulsed system clock signal; and an output joining circuit, coupled to the system pulse latch and the shadow pulse latch, to provide a data output signal in response to the at least one system latch signal and the at least one shadow latch signal.

US Patent:

7403611, Jul 22, 2008

Filed:

Sep 15, 2004

Appl. No.:

10/941154

Inventors:

Qin He - Newark CA, US
Ming Zhang - Cupertino CA, US
Ioudin Jean Chen - Saratoga CA, US

Assignee:

Fortemedia, Inc. - Cupertino CA

International Classification:

H04M 1/00
H04M 9/00

US Classification:

37942001, 37938802, 4555691

Abstract:

A small-footprint hands-free speakerphone apparatus includes a loudspeaker, at least one main microphone, at least one reference microphone, and openings for receiving sound. The loudspeaker is disposed within a speaker chamber. Each microphone is mounted in a microphone boot formed by an acoustic opaque resilient material. Each main microphone may be omni-directional or directional. Each reference microphone is omni-directional. An opening is formed in front of each microphone for receiving sound for the microphone. An opening is formed in back of each directional main microphone for receiving sound and forming directivity for the microphone. An opening is formed in the microphone boot for each reference microphone to receive sound from the loudspeaker. An opening may also be formed in the loudspeaker chamber for passing sound to the reference microphone. The apparatus may include one or more interface units to provide interface to external devices.

US Patent:

7415294, Aug 19, 2008

Filed:

Apr 11, 2005

Appl. No.:

11/103729

Inventors:

Ming Zhang - Cupertino CA, US

Assignee:

Fortemedia, Inc. - Cupertino CA

International Classification:

H04M 1/00

US Classification:

4555756, 4555501

Abstract:

A hands-free voice communication apparatus with integrated speakerphone and earpiece is described. The speakerphone includes a loudspeaker and zero, one or multiple microphones. The earpiece includes a small loudspeaker, one or more microphones, a wireless module, and a digital signal processing (DSP) module. The hands-free device support hands-free voice communication via the speakerphone or the earpiece. The earpiece is functional when removed from the speakerphone case and may be used for voice communication with privacy. When the earpiece is placed back in the speakerphone case, the speakerphone is functional and may be used for voice communication with convenience. The DSP module performs digital signal processing for both the earpiece and the speakerphone, e. g. , using different sets of parameters. The speakerphone may be a standalone device or may be part of a communication device.