Low-power programmable analog subsystem for acoustic activity detection

1 . A method, comprising:

receiving a first signal, wherein the first signal is an audio signal;

providing the first signal to a first comparison circuit;

providing the first signal to a second comparison circuit;

receiving from the first comparison circuit a first comparison signal;

receiving from the second comparison circuit a second comparison signal; and

providing a wake-up signal to a processing device based on the first comparison signal and the second comparison signal.

2 . The method of claim 1 , further comprising:

determining, by the first comparison circuit, whether the first signal satisfies a first threshold voltage condition;

determining, by the first comparison circuit, a number of instances that the first signal satisfies the first threshold voltage condition in a first period of time; and

determining, by the first comparison circuit, whether the number of instances that the first signal satisfies the first threshold voltage condition in a first period of time satisfies a first frequency condition, wherein the first comparison signal is based on whether the number of instances that the first signal satisfies the first threshold voltage condition in the first period of time satisfies the first frequency condition.

3 . The method of claim 2 , further comprising:

receiving a third comparison signal from the first comparison circuit; and

adjusting a value of a second threshold voltage condition to the first threshold voltage condition responsive to receiving the third comparison signal.

4 . The method of claim 2 , further comprising:

receiving a third comparison signal from the first comparison circuit; and

adjusting a duration associated with determining the number of instances that the first signal satisfies the first threshold voltage condition from a first value to a second value, wherein the second value is associated with the first period of time.

5 . The method of claim 2 , further comprising:

receiving a third comparison signal from the first comparison circuit; and

adjusting a value of a frequency condition associated with the number of instances that the first signal satisfies the first threshold voltage condition in a first period of time from a first value to a second value, wherein the second value is associated with the first frequency condition.

6 . The method of claim 2 , wherein determining whether the first signal satisfies a first threshold voltage condition comprises determining whether a voltage of the first signal exceeds a target voltage, and wherein the target voltage is correlated to a target volume of the audio signal.

7 . The method of claim 2 , wherein determining whether the first signal satisfies a first threshold voltage condition comprises determining whether a voltage of the first signal is less than a target voltage, and wherein the number of instances that the first signal satisfies the first threshold voltage condition in a first period of time is correlated to a frequency of the audio signal.

8 . The method of claim 1 , wherein the wake-up signal facilitates performance of operations comprising:

converting, by an analog-to-digital converter, the first signal to a digital format; and

storing the first signal in the digital format to memory.

9 . The method of claim 8 , further comprising:

obtaining, by the processing device, the first signal in the digital format; and

performing wake word detection analysis on the first signal in the digital format.

10 . A method, comprising:

receiving a first signal, wherein the first signal is an audio signal;

providing a first voltage to a first comparator;

providing the first signal to the first comparator;

receiving a first comparison signal based on output of the first comparator;

adjusting the first voltage to a second voltage in view of the first comparison signal;

receiving a second signal, wherein the second signal is indicative of an audio signal;

providing the second voltage to the first comparator;

providing the second signal to the first comparator;

receiving a second comparison signal based on output of the first comparator, wherein the second comparison signal is generated responsive to the second voltage and the second signal; and

providing a wake-up signal to a processing device responsive to the second comparison signal.

11 . The method of claim 10 , wherein the first comparison signal is correlated to a volume of an acoustic signal associated with the first signal.

12 . The method of claim 10 , further comprising:

determining a frequency that the first signal satisfies a condition associated with the second voltage, wherein the frequency that the first signal satisfies the conditions associated with the second voltage is correlated to a frequency of an acoustic signal associated with the first signal.

13 . A method, comprising:

receiving a first signal, wherein the first signal is an audio signal;

providing a first voltage to a first comparator;

providing the first signal to the first comparator;

receiving a first comparison signal based on output of the first comparator;

adjusting the first voltage to a second voltage in view of the first comparison signal

providing the first signal to a second comparator;

providing a third voltage to the second comparator;

receiving a second comparison signal based on output of the second comparator; and

adjusting the third voltage to a fourth voltage in view of the second comparison signal

providing a second signal to the first comparator, wherein the second signal is indicative of an audio signal;

providing the second signal to the second comparator;

receiving a second comparison signal from the first comparator, wherein the second comparison signal is based on the second signal and the second voltage;

receiving a third comparison signal from the second comparator, wherein the third comparison signal is based on the second signal and the fourth voltage; and

providing a wake-up signal to a processing device responsive to the second comparison signal and third comparison signal.

14 . The method of claim 13 , wherein the first comparison signal is correlated to a volume of an acoustic signal associated with the first signal.

15 . The method of claim 13 , further comprising:

determining a frequency that the first signal satisfies a condition associated with the second voltage, wherein the frequency that the first signal satisfies the conditions associated with the second voltage is correlated to a frequency of an acoustic signal associated with the first signal.