Multipath digital microphones

Patent metadata

Field	Value
Publication number	US-9673768-B2
Application number	US-201514812576-A
Country	US
Kind code	B2
Filing date	Jul 29, 2015
Priority date	Jul 29, 2015
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

Multipath digital microphone systems comprising a multipath digital audio combiner component are described. Exemplary multipath digital microphone systems can switch from conveying one digital audio signal to conveying another digital audio signal based on one or more switching criteria determined by an exemplary multipath digital audio combiner component. Provided implementations can be configured to switch from conveying one digital audio signal to conveying digital audio signal according to an algorithm to provide low-power, high dynamic range digital microphone systems, without audible artifacts associated with conventional digital microphone systems.

First claim

What is claimed is:

1. An apparatus, comprising:
a multipath digital audio combiner component comprising:
a plurality of digital audio filters operatively coupled to a plurality of analog-to-digital converters (ADCs) and configured to receive a plurality of digital audio signals having different scaling factors of an associated audio signal and configured to provide a plurality of filtered digital audio signals;
a gain and offset estimation component configured to estimate gain differences and offset differences between the plurality of filtered digital audio signals, wherein the gain and offset estimation component is further configured to estimate the offset differences on a continuous basis; and
a multiplexing component configured to switch from conveying one of a plurality of corrected digital audio signals to conveying a second one of the plurality of corrected digital audio signals, wherein the multipath digital audio combiner component is further configured to perform gain and offset correction for the plurality of filtered digital audio signals to provide the plurality of corrected digital audio signals.

2. The apparatus of claim 1 , wherein the multipath digital audio combiner component is further configured to employ the gain differences to scale at least one of the plurality of filtered digital audio signals to provide a scaled digital audio signal and configured to employ the offset differences to adjust offset associated with the plurality of filtered digital audio signals from the gain and offset estimation component.

3. The apparatus of claim 1 , wherein the multipath digital audio combiner component is further configured to control the multiplexing component to switch from conveying the one of the plurality of corrected digital audio signals to conveying the second one of the plurality of corrected digital audio signals based on the at least one of the plurality of filtered digital audio signals having a characteristic measurement above a threshold.

4. The apparatus of claim 1 , wherein the multipath digital audio combiner component is further configured to control the multiplexing component to switch from conveying the one of the plurality of corrected digital audio signals to conveying the second one of the plurality of corrected digital audio signals based on at least one of amplitude measurement, absolute value of the amplitude measurement, or root-mean-square power measurement of digitized data associated with the plurality of filtered digital audio signals.

5. The apparatus of claim 1 , wherein the multipath digital audio combiner component is further configured to control the multiplexing component to switch from conveying the one of the plurality of corrected digital audio signals to conveying the second one of the plurality of corrected digital audio signals at least one of abruptly, gradually, or based on a predefined algorithm.

6. The apparatus of claim 1 , wherein the gain and offset estimation component is further configured to perform at least one of a least squares estimation or a correlation-based estimation of the gain differences or the offset differences.

7. The apparatus of claim 1 , wherein the multipath digital audio combiner component is further configured to adjust the at least one of the plurality of filtered digital audio signals to provide the plurality of corrected digital audio signals based on the gain differences and offset differences from the gain and offset estimation component.

8. The apparatus of claim 1 , wherein the plurality of digital audio filters comprise at least one of a plurality of decimators or a plurality of low pass filters.

9. The apparatus of claim 1 , further comprising:
an output component configured to transmit a digital signal based on the plurality of digital audio signals having different scaling factors of the associated audio signal comprising at least one of a pulse-density modulation (PDM) signal, an integrated interchip sound (I2S) signal, or a Soundwire signal.

10. The apparatus of claim 9 , wherein the output component comprises at least one of a signal upsampler component or signal reshaper component configured to provide the PDM signal, or a decimation filter configured to provide the I2S signal.

11. A method, comprising:
receiving a plurality of digital audio signals having different scaling factors of an associated audio signal with a plurality of digital audio filters operatively coupled to a plurality of analog-to-digital converters (ADCs) and configured to provide a plurality of filtered digital audio signals;
estimating gain differences and offset differences between the plurality of filtered digital audio signals by a gain and offset estimation component;
performing a gain and an offset correction for the plurality of filtered digital audio signals to provide a plurality of corrected digital audio signals with a multipath digital audio combiner component and based on the gain differences and offset differences from the gain and offset estimation component; and
switching from conveying one of a plurality of corrected digital audio signals to conveying a second one of the plurality of corrected digital audio signals, based on at least one switching criteria.

12. The method of claim 11 , wherein the switching based on the at least one switching criteria comprises switching based on at least one of amplitude measurement, absolute value of the amplitude measurement, or root-mean-square power measurement of digitized data associated with the plurality of filtered digital audio signals.

13. The method of claim 11 , wherein the switching based on the at least one switching criteria comprises switching abruptly, gradually, or based on a predefined switching algorithm.

14. The method of claim 11 , wherein the estimating the gain differences and the offset differences by the gain and offset estimation component comprises performing at least one of a least squares estimation or a correlation-based estimation of the gain differences or the offset differences.

15. The method of claim 11 , wherein the receiving the plurality of digital audio signals with the plurality of digital audio filters comprises receiving the plurality of digital audio signals with at least one of a plurality of decimators or a plurality of low pass filters.

16. The method of claim 11 , further comprising:
estimating at least one of the gain differences or the offset differences on a continuous basis to account for temperature variations.

17. The method of claim 11 , further comprising:
scaling at least one of the plurality of filtered digital audio signals to provide a scaled digital audio signal and adjusting offset associated with the plurality of filtered digital audio signals based on the gain differences and the offset differences.

18. The method of claim 11 , further comprising:
transmitting a digital signal based on the plurality of digital audio signals having different scaling factors of the associated audio signal comprising transmitting at least one of a pulse-density modulation (PDM) signal, an integrated interchip sound (I2S) signal, or a Soundwire signal.

19. The method of claim 11 , wherein the switching based on the at least one switching criteria comprises switching based on the at least one of the plurality of filtered digital audio signals having a characteristic measurement above a threshold.

20. A system comprising:
at least one microelectromechanical systems (MEMS) acoustic sensor configured to receive at least one acoustic signal;
a first circ

Assignees

• Invensense Inc

Inventors

• Perrott Michael H

Classifications

• H03G3/3026 Primary

  the gain being discontinuously variable, e.g. controlled by switching · CPC title

• H04R29/006

  Microphone matching · CPC title

• H04R2430/01

  Aspects of volume control, not necessarily automatic, in sound systems · CPC title

• H03G3/3036

  in high-frequency amplifiers or in frequency-changers (H03G3/3052, H03G3/32, H03G3/34 take precedence) · CPC title

• H04H60/04

  Studio equipment; Interconnection of studios · CPC title