ADAPTIVE NOISE CANCELLATION
First Claim
1. A noise cancellation apparatus comprising:
- a first digital microphone to detect ambient noise;
a first sigma delta modulator coupled to an output of the first digital microphone;
a second digital microphone located near an earpiece speaker to detect an output of the earpiece speaker;
a second sigma delta modulator coupled to an output of the second digital microphone;
a decimator coupled to the second sigma delta modulator;
an adaptive digital filter to adaptively adjust an output of the earpiece speaker in response to the decimator and the first sigma delta modulator so that the output of the earpiece speaker includes a desired audio and an acoustic signal to cancel some or all of the ambient noise, wherein at least one coefficient of the adaptive digital filter is used to adaptively adjust the output of the earpiece speaker based on a present error sample and a delayed input sample.
1 Assignment
0 Petitions
Accused Products
Abstract
In some embodiments a noise cancellation system includes a first digital microphone to detect ambient noise, a first sigma delta modulator coupled to an output of the first digital microphone, a second digital microphone located near an earpiece speaker to detect an output of the earpiece speaker, a second sigma delta modulator coupled to an output of the second digital microphone, a decimator coupled to the second sigma delta modulator, and an adaptive digital filter to adaptively adjust an output of the earpiece speaker in response to the decimator and the first sigma delta modulator so that the output of the earpiece speaker includes a desired audio and an acoustic signal to cancel some or all of the ambient noise. Other embodiments are described and claimed.
-
Citations
22 Claims
-
1. A noise cancellation apparatus comprising:
-
a first digital microphone to detect ambient noise; a first sigma delta modulator coupled to an output of the first digital microphone; a second digital microphone located near an earpiece speaker to detect an output of the earpiece speaker; a second sigma delta modulator coupled to an output of the second digital microphone; a decimator coupled to the second sigma delta modulator; an adaptive digital filter to adaptively adjust an output of the earpiece speaker in response to the decimator and the first sigma delta modulator so that the output of the earpiece speaker includes a desired audio and an acoustic signal to cancel some or all of the ambient noise, wherein at least one coefficient of the adaptive digital filter is used to adaptively adjust the output of the earpiece speaker based on a present error sample and a delayed input sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method of noise cancellation comprising:
-
detecting an ambient noise with a first digital microphone; sigma delta modulating an output of the first digital microphone; detecting an output of an earpiece speaker with a second digital microphone; sigma delta modulating an output of the second digital microphone; decimating the sigma delta modulated output of the second digital microphone; adaptively adjusting an output of the earpiece speaker in response to the decimating and the sigma delta modulating of the output of the first digital microphone so that the output of the earpiece speaker includes a desired audio and an acoustic signal to cancel some or all of the ambient noise, wherein the adaptively adjusting of the output of the earpiece speaker is based on a present error sample and a delayed input sample. - View Dependent Claims (13, 14, 15, 20, 21, 22)
-
Specification