Feedback microphones encoder modulators, signal generators, mixers, amplifiers, summing nodes

• US 9,384,726 B2
• Filed: 01/11/2012
• Issued: 07/05/2016
• Est. Priority Date: 01/06/2012
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Le Faucheur, Laurent
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): Jerez Lora, William A
• Application Number:
  US13/348,593
• Publication Number:
  US 20120177213A1
• Time in Patent Office: 1,637 Days
• Field of Search: 381/71.2, 381/5, 381/10, 381/17, 381/19, 381/71.1, 381/71.11, 381/71.13, 381/80, 381/83, 381/94.7, 381/119, 381/120, 381/71.6
• US Class Current: 1/1
• CPC Class Codes: G06F 3/165 Management of the audio stream, e.g. setting of volume, audio stream path
• CPC Class Codes: G10K 11/17821 characterised by the analysis of the input signals only
• CPC Class Codes: G10K 11/1783 handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions
• CPC Class Codes: G10K 11/17855 for improving speed or power requirements
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 11/17885 additionally using a desired external signal, e.g. pass-through audio such as music or speech
• CPC Class Codes: H04B 1/1684 of the decoded left or right stereo channel
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04S 3/004 For headphones

Abstract

A noise-cancelling system includes headset for generating a feedback signal for noise-cancellation in response to sound externally generated from the headset. The noise-cancellation feedback signal can also be described as a noise-cancellation “feed-forward” signal. An encoded microphone signal is generated in response to the first feedback signal. An audio generator can be used to generate a noise-cancellation signal in response to the encoded microphone signal and to generate an electronic audio signal in response to the encoded microphone signal and a first output audio signal. An audio connector is provided to couple the encoded microphone signal from the headset to the audio generator and to couple the first electronic audio signal to the headset.

Claims

1. Encoder circuitry comprising:

A. first modulator circuitry having an analog, feedback microphone input and an analog output;

B. first signal generator circuitry providing a first ultrasonic carrier frequency signal and having an analog output;

C. first mixer circuitry having an analog input connected to the analog output of the first modulator circuitry, an analog input connected to the analog output of the first signal generator circuitry, and an analog output;

D. first amplifier circuitry having an analog input connected to the analog output of the first mixer circuitry and an analog output;

E. second modulator circuitry having an analog, feedback microphone input and an analog output;

F. second signal generator circuitry providing a second ultrasonic carrier frequency signal having a frequency different from the frequency of the first ultrasonic carrier frequency signal and having an analog output;

G. second mixer circuitry having an analog input connected to the analog output of the second modulator circuitry, an analog input connected to the analog output of the second signal generator circuitry, and an analog output;

H. second amplifier circuitry having an analog input connected to the analog output of the second mixer circuitry and an analog output;

I. a first summing node having a first input coupled to the analog output of the first amplifier circuitry, a second input coupled to the analog output of the second amplifier circuitry, and an output; and

J. a second summing node having a third microphone input, a second input coupled to the output of the first summing node, and an output.

2. The encoder circuitry of claim 1 including a headset having a speaker, a feedback microphone mounted on the headset proximate the speaker, and an audio microphone, the feedback microphone having an analog feedback microphone output coupled to the analog, feedback microphone input, the audio microphone having an analog output coupled with the analog output of the first amplifier circuitry.

3. The encoder circuitry of claim 2 including a jack having a speaker terminal and a microphone terminal, the speaker having an input that is coupled to the speaker terminal through a lead, and the audio microphone and the analog output of the first amplifier circuitry being coupled to the microphone terminal through respective leads.

4. The encoder circuitry of claim 1 in which the first and second modulator circuitry are baseband modulator circuitry.