Noise reduction method and apparatus, and mobile terminal

1. A mobile terminal comprising:

a processor;

an audio output device configured to output audio;

a sensor configured to generate an acceleration signal of the mobile terminal;

a noise reduction signal determining circuit configured to:

obtain the acceleration signal of the mobile terminal when the audio output device is in a working state,

integrate the acceleration signal to generate a rate signal,

calculate a shift signal based on the rate signal to obtain a vibration waveform of the mobile terminal when the mobile terminal vibrates, and

invert the vibration waveform to obtain a noise reduction signal; and

a coupling circuit configured to superimpose the noise reduction signal onto to-be-output audio of the audio output device.

2. The mobile terminal according to claim 1 , wherein the noise reduction signal determining circuit comprises:

a first integrator circuit configured to integrate the acceleration signal to generate the rate signal; and

a second integrator circuit configured to integrate the rate signal to generate the vibration waveform of the mobile terminal.

3. The mobile terminal according to claim 2 , wherein the first integrator circuit comprises a resistor R 1 , a resistor R 2 , a capacitor C 1 , a capacitor C 2 , and an operational amplifier U 1 ,

wherein a first end of the resistor R 1 receives the acceleration signal, a second end of the resistor R 1 is electrically connected to an in-phase input end of the operational amplifier U 1 and a first end of the capacitor C 1 separately, and a second end of the capacitor C 1 is grounded, and

wherein a first end of the resistor R 2 is grounded, a second end of the resistor R 2 is electrically connected to a reverse-phase input end of the operational amplifier U 1 and a first end of the capacitor C 2 separately, and an output end of the operational amplifier U 1 outputs the rate signal.

4. The mobile terminal according to claim 3 , wherein the second integrator circuit comprises a resistor R 3 , a resistor R 4 , a capacitor C 3 , and an operational amplifier U 2 ,

wherein the output end of the operational amplifier U 1 is electrically connected to a first end of the resistor R 3 and a second end of the capacitor C 2 separately, and

wherein a second end of the resistor R 3 is electrically connected to a reverse-phase input end of the operational amplifier U 2 and a first end of the capacitor C 3 separately, a first end of the resistor R 4 is grounded, a second end of the resistor R 4 is electrically connected to an in-phase input end of the operational amplifier U 2 , and an output end of the operational amplifier U 2 is connected to a second end of the capacitor C 3 .

5. The mobile terminal according to claim 2 , further comprising:

a phase-shift circuit configured to shift forward or shift backward a phase of the determined vibration waveform.

6. The mobile terminal according to claim 4 , further comprising:

a phase-shift circuit configured to shift forward or shift backward the vibration waveform,

wherein the phase-shift circuit comprises a resistor R 5 and a capacitor C 4 ,

wherein the output end of the operational amplifier U 1 is electrically connected to the first end of the resistor R 3 by using the resistor R 5 , and

wherein a first end of the resistor R 5 is electrically connected to the output end of the operational amplifier U 1 and the second end of the capacitor C 2 separately, a second end of the resistor R 5 is electrically connected to the first end of the resistor R 3 , a first end of the capacitor C 4 is grounded, and a second end of the capacitor C 4 is connected between the resistor R 5 and the resistor R 3 .

7. The mobile terminal according to claim 6 , wherein the coupling circuit comprises a capacitor C 5 , and

wherein a first end of the capacitor C 5 is electrically connected to the output end of the operational amplifier U 2 and the second end of the capacitor C 3 separately, and a second end of the capacitor C 5 is connected to the audio output device.

8. A mobile terminal comprising:

a sensor configured to generate an acceleration signal of the mobile terminal;

an audio output device configured to output audio;

a memory configured to store software instructions; and

a processor configured to execute the software instructions to:

obtain the acceleration signal of the mobile terminal when the audio output device is in a working state;

integrate the acceleration signal to generate a rate signal;

calculate a shift signal based on the rate signal to obtain a vibration waveform of the mobile terminal when the mobile terminal vibrates;

invert the vibration waveform to obtain a noise reduction signal; and

superimpose the noise reduction signal onto to-be-output audio of the audio output device.

9. The mobile terminal according to claim 8 , wherein the processor is further configured to:

shift forward or shift backward the determined vibration waveform by a phase.

10. The mobile terminal according to claim 8 , wherein the processor is further configured to:

adjust the acceleration signal to make an amplitude of the adjusted acceleration signal fall within a predetermined amplitude range; and

determine, based on the adjusted acceleration signal, the vibration waveform of the mobile terminal when the mobile terminal vibrates.

11. A noise reduction method, applicable to a mobile terminal, which is provided with an audio output device configured to output audio, wherein the method comprises:

generating an acceleration signal of the mobile terminal when the audio output device is in a working state;

integrating the acceleration signal to generate a rate signal;

calculating a shift signal based on the rate signal to obtain a vibration waveform of the mobile terminal when the mobile terminal vibrates;

inverting the vibration waveform to obtain a noise reduction signal; and

superimposing the noise reduction signal onto to-be-output audio of the audio output device.

12. The method according to claim 11 , wherein before inverting the determined vibration waveform, the method further comprises:

shifting forward or shifting backward the determined vibration waveform by a phase.

13. The method according to claim 11 , wherein before determining the vibration waveform of the mobile terminal when the mobile terminal vibrates, the method further comprises:

adjusting the acceleration signal to make an amplitude of the adjusted acceleration signal fall within a predetermined amplitude range.