KR20070038760A - Apparatus for reducing noise in a terminal - Google Patents

Abstract

The present invention relates to an apparatus for removing noise in a terminal, comprising: an antenna for transmitting and receiving radio frequency signals, an audio chip for generating or processing an audio signal, and a voice input / output device for outputting the audio signal or receiving an audio signal from the outside; And a noise removing unit for removing a signal causing interference with the radio frequency signal of the antenna among the audio signals transmitted and received by the input / output device. In addition, the terminal according to the present invention comprises an audio chip for generating an audio signal, a speaker connected to the audio chip and an audio line to output the audio signal, and a low pass filter positioned in the audio line. There is an effect of preventing the performance degradation of the antenna by the signal.

Description

Noise reduction device in the terminal {APPARATUS FOR REDUCING NOISE IN A TERMINAL}

1 is a block diagram of an audio signal processor including a noise removing device according to the prior art.

2 is a block diagram of a mobile communication terminal according to the present invention.

3 is a block diagram of an audio signal processing unit including a noise removing device according to the present invention.

5 is a first layout view of an antenna and an audio device to which the present invention can be applied.

5 is a second layout view of an antenna and an audio device to which the present invention can be applied.

6 is a third layout view of an antenna and an audio device to which the present invention can be applied.

** Description of the symbols for the main parts of the drawings **

1 to 3, 13, 103: Speaker 4: Antenna

11, 101: audio chip 12, 102: capacitor

104: noise canceller 105: microphone

106: control unit 107: memory

108: power supply unit 109: keypad

110: display unit 111: RF module unit

112: baseband processing unit

The present invention relates to a noise canceling device in a terminal, and more particularly, to a noise canceling device in a terminal for filtering a signal that may interfere with a radio frequency signal among audio signals.

The mobile communication terminal extends through a wireless communication device capable of making a call with a general telephone subscriber or another mobile communication subscriber through a base station in a wireless zone while arbitrarily moving in a mobile communication area.

In general, a mobile communication terminal uses less time for communication and a longer time for waiting or carrying for communication, and various additional services are developed to increase the low utilization rate and convenience of use of the mobile communication terminal. It is provided.

Additional services provided to mobile carriers include wireless Internet access, short message service, multimedia message transmission, program download, wireless online games, etc. Phone Book), MP3, Notepad, Schedule Management, Games, Video and Still Cameras, Wake-up Calls, Call-Forwarding, and more. Additional services are still being developed.

In order to provide the above additional services to the user, the audio device embedded in the mobile communication terminal is also progressing, and in order to provide more improved sound quality, the mobile communication terminal has a circuit for removing noise.

1 is a block diagram of an audio signal processor including a noise removing device according to the prior art. As shown here, the audio signal processor includes an audio chip 11 for generating an audio signal, a capacitor 12 connected in parallel to the audio chip 11 to remove noise, and the audio chip 11. And a speaker 13 connected through an audio line to output the audio signal.

In general, the capacitor 12 is located closer to the audio chip 11 than the speaker 13, and is connected in parallel with each audio line to remove noise generated in the audio signal by the antenna. do.

If a high frequency noise signal is present among the signals transmitted along the audio line, the noise signal may be removed through a grounded capacitor. Capacitors are short circuited when very high frequency signals pass through and open circuited when very low frequency signals pass, so noise signals flow to ground and the signal corresponding to the sound source is passed to the speaker.

When the distance between the antenna and the speaker is far, since the influence of the audio signal on the transmission and reception signal of the antenna is small, the interference phenomenon can be prevented only by the capacitor 12 as described above, but when the distance between the speaker and the antenna is still close There is a problem that cannot be prevented.

In particular, as the size of the mobile communication terminal decreases, the distance between the audio signal processing unit and the antenna is shortened, so that the audio signal has an increasing influence on the antenna performance.

The present invention has been proposed to solve the above problems, and an object of the present invention is to remove a noise component induced by an antenna in an audio line to prevent interference between an audio signal and an RF signal. The present invention provides a noise canceling device.

It is another object of the present invention to add a low pass filter to an audio line connected to a speaker so that a low frequency sound source signal can be transmitted to the speaker and remove only noise components that can be induced to the antenna side. In providing.

Another object of the present invention is to provide an apparatus for removing noise of an audio signal of a terminal, by connecting an inductor in series to an audio line connected to a speaker so as to remove noise components that may be induced to the antenna side.

In order to achieve the above object, the terminal according to the present invention, an antenna for transmitting and receiving radio frequency signals, an audio chip for generating or processing an audio signal, and the voice for outputting the audio signal or receiving an audio signal from the outside And an noise canceling unit for removing an input / output device and a signal causing interference with the radio frequency signal of the antenna among the audio signals transmitted and received by the input / output device.

In addition, in order to achieve the above object, the terminal according to the present invention, an audio chip for generating an audio signal, a speaker connected to the audio chip and an audio line to output the audio signal, and to the audio line And a low pass filter positioned.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2 is a configuration diagram of a mobile communication terminal according to the present invention, and as shown therein, a control unit 106 for controlling the overall operation of the mobile communication terminal, and a microcode of a program for processing and controlling the control unit 106. And a memory 107 for storing various kinds of reference data, a keypad 109 for receiving a user's instruction, a display unit 110 for displaying a result of the processing by the controller 106, and a received antenna. An RF module 111 for transmitting a radio frequency (RF) signal to the baseband processor 112 and a baseband processor for processing and transmitting a signal received from the RF module 111 to the controller 106. 112, an audio chip 101 for generating or processing an audio signal, a noise canceller 104 for removing noise of the audio signal, a microphone 105 for receiving an external sound source, and each of the above components Power on It is composed of a power supply unit 108 for supplying.

The noise removing unit 104 removes noise of an audio signal in order to prevent an interference phenomenon on the antenna side when the audio chip 101 is located close to the antenna. In the process of outputting the audio signal generated by the audio chip 101 through the speaker 103, the high frequency noise mixed in the audio signal is induced in the antenna may cause interference. Therefore, in order to pass only a low frequency signal corresponding to a sound source among audio signals and to block only a high frequency signal that may interfere with the RF signal of the antenna, a low pass filter may be used as the noise canceller 104. In this case, the low pass filter may be implemented as an inductor connected in series to an audio line connecting the audio chip 101 and the speaker 103.

3 is a block diagram of an audio signal processor according to an embodiment of the present invention. As shown in FIG. 3, an audio chip 101 for generating an audio signal and a parallel connection with the audio chip 101 may be used to remove an RF signal of an antenna, or A capacitor 102 for removing noise due to interference between the RF signal and the audio signal, a speaker 103 for outputting an audio signal, and a high frequency connection between the audio chip 101 and the speaker 103 in series The noise canceller 104 removes the signal. That is, the audio signal processor according to the present invention further includes a noise canceller 104 in the configuration of the existing audio signal processor.

는,

로 표현될 수 있기 때문에 인덕터스 L의 값이 상수일 때 주파수가 높을수록 임피던스가 커져 고 주파수 신호를 차단할 수 있다. 반면, 오디오 신호의 주파수가 매우 낮은 경우 잡음 제거부(104)의 임피던스는 0값에 가까워져 오디오 신호가 스피커(103)에 바로 전달될 수 있다. 따라서, 상기 잡음 제거부(104)는 고주파수 신호에 대하여 개방 회로(open circuit)로 동작하고, 저주파수 신호에 대하여 단락 회로(short circuit)로 동작한다. The noise canceller 104 may be implemented using an inductor having a high impedance with respect to a high frequency signal. Impedance of inductor

Is,

Since the value of inductor L is a constant, the higher the frequency, the greater the impedance, which can block a high frequency signal. On the other hand, when the frequency of the audio signal is very low, the impedance of the noise canceling unit 104 is close to zero value, the audio signal can be directly transmitted to the speaker 103. Therefore, the noise canceller 104 operates as an open circuit for the high frequency signal and operates as a short circuit for the low frequency signal.

The RF signal transmitted and received from the antenna and the signal causing interference are high frequency signals, and the signal (sound source) to be output through the speaker 103 is a low frequency signal, and thus an inductor is connected in series between the audio chip 101 and the speaker 103. When connected, only the sound source can be delivered to the speaker 103.

The inventor of the present application measured the transmission power and the reception sensitivity of the mobile communication terminal implementing the noise canceling unit 104 as an inductor, and the measurement results are shown in Table 1 below.

Performance GSM (dBm) DCS (dBm) PCS (dBm)  Transmit power Inductor Use 28 24 24 No inductor 28 26 25  Receiving sensitivity Inductor Use 102 103 102 No inductor 103.4 104.5 103

In order to increase the reliability of the measurement, antenna performance was measured using mobile communication terminals using different communication systems. Table 1 shows measurement results of terminals using a mobile communication system of a global system for mobile communication (GSM), a digital cellular system (DCS), and a personal communication system (PCS), respectively. As shown in Table 1, it can be seen that both the transmission power and the reception sensitivity of the terminal are slightly improved than before the inductor is used.

Here, the noise canceller 104 may be implemented using various low pass filters in addition to the inductor connected in series.

4 is a first layout view of an antenna and an audio device to which the present invention can be applied. As shown here, when the built-in antenna 4 is located at the bottom of the mobile communication terminal, a) when the microphone 1 is close to the antenna 4, b) the speaker 2 is in front of the antenna 4 or If located behind, c) the noise canceling unit according to the invention can be applied if the speaker 3 is located on both sides of the antenna 4. In this case, the noise canceling unit is located in front of the microphone 1 or the speakers 2 and 3 and filters the noise signal of the high frequency mixed with the audio signal so as not to affect the antenna 4.

Here, the present invention can be applied to all types of mobile communication terminals such as a bar type, a folder type, a slide type, and a swing type.

5 is a second layout view of an antenna and an audio device to which the present invention can be applied. As shown here, when the built-in antenna 4 is located above the mobile communication terminal, a) when the microphone 1 is close to the antenna 4, b) the speaker 2 is in front of the antenna 4; Or, if located behind, c) when the speaker (3) is located on both sides of the antenna (4) can apply the noise canceling unit according to the invention. That is, when a voice input / output device such as a microphone or a speaker is disposed close to the antenna regardless of the position of the antenna, a noise canceling unit is added to the front of the voice input / output device so that the noise signal is not induced to the antenna.

6 is a third layout view of an antenna and an audio device to which the present invention can be applied. As shown here, when the external antenna 4 is located on top of the mobile communication terminal, a) when the microphone 1 is close to the antenna 4, b) the speaker 2 is below the antenna 4; When located inside, c) when the speaker 3 is located on both sides close to the antenna (4) can apply the noise canceling unit according to the present invention.

That is, in the mobile communication terminal using the external antenna as shown in FIG. 4 and FIG. 5 as well as the mobile communication terminal using the external antenna as shown in FIG. Through this, high frequency signals that cause interference can be eliminated.

As described above, the noise canceling device according to the present invention is equipped with a filter for removing a noise signal in front of the voice input / output device when the voice input / output device such as a speaker or a microphone is located close to the antenna. There is an effect of preventing deterioration of the performance of the antenna.

In addition, the noise canceling apparatus according to the present invention removes the noise signal mixed with the audio signal before delivering the audio signal to the speaker, thereby improving the sound quality output to the speaker.

Claims (9)

An antenna for transmitting and receiving radio frequency signals, An audio chip for generating or processing audio signals, An audio input / output device for outputting the audio signal or receiving an audio signal from the outside; And a noise removing unit for removing a signal causing interference with the radio frequency signal of the antenna among the audio signals transmitted and received by the input / output device. The method of claim 1, The voice input and output device is a noise removing device in the terminal, characterized in that the speaker or microphone. The noise canceling apparatus of claim 1, wherein the noise canceling unit is mounted for each audio line connecting the audio chip and the voice input / output device. The noise canceling apparatus of claim 1, wherein the noise canceling unit is a low pass filter. The noise canceling device of claim 1, wherein the noise canceling unit is an inductor connected in series with the voice input / output device. The apparatus of claim 1, wherein the antenna is an external antenna. The apparatus of claim 1, wherein the antenna is a built-in antenna. An audio chip for generating an audio signal, A speaker connected to the audio chip and an audio line to output the audio signal; And a low pass filter positioned at the audio line. 10. The apparatus of claim 8, wherein the low pass filter is an inductor connected in series with the audio line.

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