KR20060004284A - Apparatus for decreasing electric field noise in case of receiving audio am small electric field - Google Patents

Abstract

The present invention relates to an electric field noise reduction apparatus for receiving an audio AM weak field, comprising: an AM tuner for selecting a specific AM frequency; An output unit for outputting an output signal of the AM tuner as a voice signal; And a high-cut control circuit receiving an SM terminal voltage according to electric field strength from the AM tuner and receiving an audio output signal of the AM tuner. And a capacitor connected at one side to an audio output signal output terminal of the AM tuner and at the other end to a high-cut control circuit. Therefore, when AM is received, a capacitor and a high-cut control circuit are added to the output of the AM tuner, so that the high-frequency noise signal of the audio signal in the weak field is operated by the high-cut control circuit to bypass the capacitor and pull out the noise to ground to block the noise. Can provide clear sound quality.

Audio, AM, Weak Field, Noise, Reduction

Description

Audio A.M. Apparatus for decreasing electric field noise in case of receiving audio AM small electric field}

1 is a block diagram of a conventional audio AM receiver.

2 is a block diagram of a device for reducing electric field noise when receiving an audio AM weak electric field according to the present invention;

         <Explanation of Signs of Major Parts of Drawings>

10: AM tuner 11: output adjustment element

12 capacitor 13 high-cut control circuit

20: Microcomputer 30: Volume IC

40: power IC 50: speaker

The present invention relates to a device for reducing electric field noise when receiving an audio AM weak field, and in particular, by adding a capacitor and a high-cut control circuit to an AM tuner output terminal when receiving AM, audio is introduced through the antenna by the SM terminal voltage of the AM tuner. Determining the electric field strength of the AM frequency, operating the high-cut control circuit only in the weak field, bypassing the high frequency noise signal from the capacitor, and connecting it to ground to cut off the noise of the audio signal. It is about.

1 is a block diagram of a conventional audio AM receiver.

In the case of car audio, an AM tuner 10 which is mounted at a predetermined position of a vehicle and connected to an antenna for receiving radio waves and is connected to the AM tuner 10 that selects a specific AM frequency, adjusts the output gain level of the audio. An output adjusting element 11 for adjustment, a microcomputer 20 connected to an SM (Signal Meter) terminal of the AM tuner 10 to perform automatic tuning and other overall audio control functions during AM reception, and the output A volume IC 30 connected to the adjusting element 11 to adjust an electronic volume of the audio signal, and a power IC connected to the volume IC 30 to amplify the power of the audio signal according to the adjusted volume ( 40, and a speaker 50 for outputting the audio signal amplified by the power IC (40).

However, since a weak signal is received in the weak electric field during AM reception in an audio system, the electric field noise generated when the electronic device is operated is relatively influent, and thus, it is difficult to listen to the signal according to the noise during AM audio broadcast reception.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the problems of the prior art, and an object of the present invention is to add a capacitor and a high-cut control circuit to an AM tuner output to reduce noise during AM reception in an audio system. The terminal voltage is used to determine the electric field strength of the AM frequency introduced through the antenna, so that the high-cut control circuit does not operate in the case of heavy and strong electric fields. The capacitor is opened to transmit the original AM audio signal to the output unit. In the weak field, a high-cut control circuit operates to bypass high-frequency noise signals from a capacitor and connect them to ground to block the noise of an AM audio signal.

In order to achieve the object of the present invention, the present invention provides an AM receiver, comprising: an AM tuner for selecting a specific AM frequency; An output unit for outputting an output signal of the AM tuner as a voice signal; And a high-cut control circuit receiving an SM terminal voltage according to electric field strength from the AM tuner and receiving an audio output signal of the AM tuner. And a capacitor connected at one side to an audio output signal output terminal of the AM tuner and at another side to a high-cut control circuit.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail the configuration and operation. This embodiment is not intended to limit the scope of the invention, but is presented by way of example only.

2 is a block diagram of an electric field noise reduction apparatus when receiving an audio AM weak electric field according to the present invention.

Referring to FIG. 2, an AM tuner 10, an output adjusting element 11, a microcomputer 20, a volume IC 30, a power IC 40 of an existing audio AM receiver, In the existing components of the audio AM receiver of the speaker 50, a capacitor 12 and a high-cut control circuit 13 according to the present invention are added to remove high frequency noise only in the weak field of the AM audio signal. can do.

An AM tuner 10 mounted at a predetermined position of a vehicle and connected to an antenna for receiving radio waves, and for selecting a specific AM frequency, and connected to the AM tuner 10 to adjust an output gain level of an AM audio signal Connected to the output adjustment element 11, the SM terminal of the AM tuner 10, the microcomputer 20 to perform automatic tuning and other overall audio control functions during AM reception, and the output adjustment element 11 A volume IC 30 for adjusting an electronic volume of an audio signal, a power IC 40 for amplifying a power of an AM audio signal according to the adjusted volume connected to the volume IC 30, and the power IC In the audio AM receiver provided with the speaker 50 for outputting the AM audio signal amplified from 40,

One side is connected to the AM tuner output terminal (AM AF-out terminal), the other side is connected to the high-cut control circuit 13, and at the weak electric field (voltage corresponding to AM 35 dB or less), the high-cut control circuit 13 ) Is operated so that the high frequency noise signal is bypassed and connected to the ground, and above the medium electric field (voltage corresponding to AM 50-60 dB or more) and the high electric field (voltage corresponding to AM 60 dB or more) The capacitor 12 that is open because the high-cut control circuit 13 is inoperative,

One side is connected to the other side of the capacitor 12, the other side is ground (Ground), SM terminal is connected to one side of the AM tuner 10, the DC voltage is output to the SM (Signal Meter) terminal according to the electric field strength The field strength of the received frequency is determined by receiving a voltage to distinguish a weak electric field, a medium electric field, and a strong electric field, and when determined to be the weak electric field, the high frequency noise signal is bypassed from the capacitor 12 to ground. The high-cut control circuit 13 is connected to remove the noise.

When the high-cut control circuit 13 receives the SM terminal voltage of the AM tuner 10 and determines that it is a weak electric field, the high-cut control circuit 13 operates to output a high frequency noise signal to the capacitor 12. Bypass through to connect to the ground (Ground) to cut off the high-frequency noise of the audio signal, the high-cut control circuit 13 does not operate in the middle and high field abnormality, so the capacitor 12 is automatically opened The original AM audio signal is transmitted as it is to output an AM audio signal to an output unit including the output adjusting element 11, the volume IC 30, the power IC 40, and the speaker 50. Thus, the high frequency noise of the AM audio signal can be cut off in the weak electric field.

Therefore, when the capacitor 12 and the high-cut control circuit 13 are added to an AM tuner output (AF-out) to reduce noise of an audio signal, high-quality sound is cut in not only a weak electric field but also a medium / strong electric field so that the sound quality is improved. The high-cut control circuit 13 is operated only in the weak field by the capacitor 12 so that a high frequency noise signal is bypassed from the capacitor 12 and connected to ground. Since the high-cut control circuit 13 is not operated in the system and the strong electric field, the capacitor 12 is opened to transmit the original AM audio signal as it is, so that the output adjusting element 11, the volume IC 30, An AM audio signal is output to an output unit including the power IC 40 and the speaker 50.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below. Or it may be modified.

As described above, the electric field noise reduction device when receiving an audio AM weak electric field according to the present invention adds a capacitor and a high-cut control circuit to an AM tuner output to reduce noise when AM is received in an audio system. The high-cut control circuit operates in the weak field by judging the electric field strength of the AM frequency introduced through the antenna using voltage, and the high-frequency noise signal is bypassed from the capacitor and grounded to block the noise. Since the high-cut control circuit is not operated above the strong electric field, the capacitor is opened so that the original AM audio signal is output to the speaker through the output control element, the volume IC, and the power IC, so that the noise of the audio is removed from the weak electric field, thereby providing clean AM audio quality. There is an effect that can listen to.

Claims (3)

In AM receiver, An AM tuner for selecting a particular AM frequency; An output unit for outputting an output signal of the AM tuner as a voice signal; A high-cut control circuit which receives an SM terminal voltage according to electric field strength from the AM tuner and receives an audio output signal of the AM tuner; And And a capacitor connected to the audio output signal output terminal of the AM tuner and the other end connected to a high-cut control circuit. The method of claim 1, The AM receiver includes an AM tuner for selecting a specific AM frequency, an output adjusting element for adjusting an output gain level of an audio signal, a microcomputer connected to the AM tuner for controlling an audio system, and a volume IC for adjusting an electronic volume of an audio signal. And a power IC for amplifying the power of the audio signal according to the adjusted volume, and a speaker for outputting the amplified audio signal, wherein the output unit includes the output adjusting element, the volume IC, the power IC, and the speaker. An electric field noise reduction device when receiving an audio AM weak electric field. The method according to claim 1 or 2, The high-cut control circuit is a high-cut control circuit that receives the SM terminal voltage of the AM tuner and operates so that the high frequency signal is bypassed through the capacitor and connected to ground only when it is determined to be a weak electric field. An electric field noise reduction device when receiving an audio AM weak electric field.

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