SYSTEM AND METHOD FOR PROCESSOR WAKE-UP BASED ON SENSOR DATA

• US 20140257821A1
• Filed: 03/07/2013
• Published: 09/11/2014
• Est. Priority Date: 03/07/2013
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Analog Devices, Inc.
• Inventors: Adams, Robert, Mortensen, Maikael
• Granted Patent: US 9,349,386 B2
• Time in Patent Office: Days
• US Class Current: 704/275
• CPC Class Codes: G06F 1/3206 Monitoring of events, devices or parameters that trigger a change in power modality
• CPC Class Codes: G10L 15/28 Constructional details of speech recognition systems
• CPC Class Codes: G10L 2015/088 Word spotting
• CPC Class Codes: G10L 2025/783 based on threshold decision
• CPC Class Codes: G10L 2025/786 Adaptive threshold
• CPC Class Codes: G10L 21/06 Transformation of speech into a non-audible representation, e.g. speech visualisation or speech processing for tactile aids G10L15/26 takes precedence
• CPC Class Codes: G10L 25/48 specially adapted for particular use
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10
• CPC Class Codes: G10L 25/84 for discriminating voice from noise
• CPC Class Codes: G10L 25/87 Detection of discrete points within a voice signal
• CPC Class Codes: G10L 25/93 Discriminating between voiced and unvoiced parts of speech signals G10L25/90 takes precedence

Abstract

A system for processor wake-up based on sensor data includes an audio buffer, an envelope buffer, and a processor. The audio buffer is configured to store a first data from a sensor. The first data is generated according to a first sampling rate. The envelope buffer is configured to store a second data, which is derived from the first data according to a second sampling rate, which is less than the first sampling rate. The processor is configured to wake up periodically from an idle state and read the second data from the envelope buffer. If the second data indicates an activity, the processor is configured to read the first data from the audio buffer. If the second data does not indicate an activity, the processor is configured to return to the idle state.

Claims

1. A system, comprising:

an audio buffer configured to store a first data from a sensor, wherein the first data is generated according to a first sampling rate;

an envelope buffer configured to store a second data, wherein the second data is derived from the first data according to a second sampling rate, and wherein second sampling rate is less than the first sampling rate; and

a processor configured to wake up periodically from an idle state and read the second data from the envelope buffer, wherein if the second data indicates an activity, the processor is configured to read the first data from the audio buffer.

2. The system of claim 1, wherein if the second data does not indicate an activity, the processor is configured to return to the idle state.

3. The system of claim 1, wherein the activity is indicated by comparing a function of the second data with a predetermined threshold.

4. The system of claim 1, further comprising an analog-to-digital converter configured to generate the first data in a digital format according to the first sampling rate from an analog signal.

5. The system of claim 1, further comprising a direct memory access (DMA) controller that facilitates reading the audio buffer and the envelope buffer.

6. The system of claim 1, wherein the envelope buffer is shorter than the audio buffer.

7. The system of claim 1, further comprising a timer configured to send an interrupt to the processor periodically, wherein the processor is configured to wake up on receiving the interrupt.

8. The system of claim 1, further comprising:

an envelope detector configured to detect an envelope of the first data; and

a decimator configured to downsample the envelope to generate the second data according to the second sampling rate.

9. The system of claim 8, further comprising a bandpass filter configured to filter the first data and feed the filtered data to the envelope detector.

10. The system of claim 9, wherein the first data is generated from audio signals.

11. The system of claim 10, wherein the activity comprises an onset of a voice signal.

12. The system of claim 10, wherein the bandpass filter is configured to filter out frequencies in the first data beyond a normal human voice range to generate a subset of the first data.

13. The system of claim 10, wherein the system is configured to perform operations comprising:

detecting the envelope of the subset;

determining a difference between the envelope and a negative peak value; and

detecting an activity if the difference exceeds a predetermined threshold.

14. The system of claim 10, wherein the detecting the envelope is based on a parameter of the subset selected from a group consisting of:

root mean square (RMS), average, peak and quasi-peak.

15. The system of claim 10, wherein the system is configured to perform further operations comprising:

normalizing the envelope of the subset;

comparing the normalized envelope with a second negative peak value;

if the normalized envelope is not less than the second negative peak value during a predetermined number of clock cycles, incrementing the second negative peak value by a fixed amount to obtain the negative peak value; and

if the normalized envelope is less than the second negative peak value, setting the negative peak value to the second negative peak value.

18. The system of claim 10, wherein the envelope detector comprises a portion of a voice activity detector.

19. The system of claim 1, wherein the system is configured to perform operations comprising:

determining that the activity occurred between two consecutive wake-up times;

executing a keyword matching algorithm on the first data in the audio buffer; and

if a matching keyword is found, performing another task based on the matching keyword.

20. The system of claim 1, wherein the processor comprises at least one of a digital signal processor and a microcontroller.

16. The system of claim 16, wherein the normalizing the envelope comprises a log normalization of the envelope.

17. The system of claim 16, wherein the normalizing the envelope comprises taking a ratio of energies represented by the first data.