Noise removal method and system
A method and system for removing noise due to bias electric power (MIC_Bias) or Time Division Multiple Access (TDMA) noise are provided. The system includes an interface with a microphone contact, for connecting to an accessory, an Analog-to-Digital (AD) converter for converting an analog voltage level, input via the microphone contact, into a digital voltage level, an audio processing unit for processing an audio signal input via the microphone contact, a switch for at least one of connecting and disconnecting the microphone contact and the AD converter, and a controller. The controller compares the digital voltage level with voltage levels stored in a look up table. The controller identifies a type of accessory connected to the interface. The controller also switches off the switch to prevent noise from being introduced into the audio signal via a wire connecting the microphone contact and the AD converter.
1. A noise removal system, the system comprising:
an interface including a microphone contact, configured to connect to an accessory;
an Analog-to-Digital (AD) converter configured to convert an analog voltage level, input via the microphone contact, into a digital voltage level;
an audio processing unit configured to process an audio signal input via the microphone contact;
a switch configured to connect or disconnect the microphone contact and the AD converter; and
a controller configured to identify a type of accessory connected to the interface by comparing the digital voltage level with voltage levels stored in a storage unit, and to switch off the switch to disconnect the microphone contact and the AD converter after identifying the type of accessory.
2. The system of claim 1 , further comprising:
a sensing unit configured to determine whether the accessory is connected to the interface and to output a connection state to the controller,
wherein the controller receives a signal, indicating that the accessory is removed from the interface, from the sensing unit, and switches the switch on.
3. The system of claim 2 , wherein the interface comprises a detection contact, and wherein the sensing unit detects a change in a voltage level of the detection contact and outputs a signal to the controller indicating whether the accessory is connected to the interface.
4. The system of claim 3 , wherein the interface comprises a ground contact, and wherein the detection contact is connected to the ground contact when the accessory is inserted into the interface, and disconnected from the ground contact when the accessory is removed from the interface.
5. The system of claim 3 , wherein the voltage level of the detection contact increases from the ground voltage level to a bias voltage level, or decreases from the bias voltage level to the ground voltage level, when the accessory is connected to the interface.
6. The system of claim 4 , wherein the noise comprises Time Division Multiple Access (TDMA) noise.
7. A method for removing noise in a system that includes an interface including a microphone contact for connecting to an accessory, an Analog-to-Digital (AD) converter for converting an analog voltage level input via the microphone contact into a digital voltage level, and a switch for connecting or disconnecting the microphone contact and the AD converter, the method comprising:
determining whether an accessory is connected to the interface;
identifying a type of accessory connected to the interface by comparing the digital voltage level with voltage levels stored in a storage unit; and
switching off the switch to disconnect the microphone contact and the AD converter after identifying the type of accessory.
8. The method of claim 7 , further comprising:
switching on the switch to connect the microphone contact and the AD converter when the accessory is removed from the interface.
9. The method of claim 8 , wherein the interface comprises a detection contact and a ground contact.
10. The method of claim 9 , wherein a voltage level of the detection contact increases from the ground voltage level to a bias voltage level, or decreases from the bias voltage level to the ground voltage level, when the accessory is connected to the interface.