JP2003179509A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a constitution thin and effectively and to efficiently and inexpensively establish the compatibility between an AM receiver circuit and a digital electronic circuit as a noise generating source. <P>SOLUTION: A receiver is provided with a tuner 5 provided inside a receiver body 4 and capable of receiving the AM-band, an AM loop antenna 1 connected to the tuner 5 via a connection cable 2, and a noise generating source 6 provided in the same case as that of the body 4 of the tuner 5 and generating a radiation noise. In the noise source 6, a higher harmonic of one-digit multiple of the frequency of the radiation noise corresponds to the frequency of the reception frequency band of the AM tuner 5. The cable 2 has an enough length to keep a prescribed distance between the loop antenna body 1 and the body 4 so that the body 1 may not be affected by the radiation noise of the noise source 6, and is formed of a two core shielding wire whose skin portion is covered with a copper shield 3. The shield 3 takes in the radiation noise of the noise source 6 and makes the noise to flow to a ground section 8. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus having an AM tuner such as an AM / FM tuner or an AV receiver having an AM / FM tuner circuit and an amplifier built therein and capable of receiving by an AM loop antenna.

[0002]

2. Description of the Related Art In recent years, internal electronic circuits of electric products have been digitized in accordance with higher performance and have come to include various clock frequencies. Among them, several tens of kHz to several hundreds of kHz
For equipment with a built-in AM receiving circuit, the frequency of Hz is several times higher than that, and harmonics are superimposed on the AM receiving band, causing a problem. Therefore, it is necessary to digitize switching power supplies and amplifier circuits in equipment with an AM receiving circuit. In order to do this, certain measures were necessary.

FIG. 2 showing an example of an AM receiving apparatus having a conventional AM loop antenna apparatus with reference to the drawings.
It will be described based on. In FIG. 2, the AM loop antenna 1 is used as a receiver having the AM loop antenna 11.
AM tuner 1 in which 1 is connected via a connection cable 12
If, for example, a switching power supply circuit 15 that is a source of radiation noise that causes reception interference is present inside the AV receiver body 14 that incorporates 3, the AM loop antenna 11 is normally separated from the AV receiver body 14 by any amount. ,
The harmonics of the interference frequency generated by the switching power supply circuit 15 are radiated to the connection cable 12 and superposed on the AM antenna circuit to be mixed therewith to cause reception interference. Therefore, the switching power supply circuit 15 is shielded by the shield means 16 to prevent the radiation noise from affecting the antenna circuit.

[0004]

As described above, the conventional A
When an M loop antenna and an electronic circuit including an interfering wave such as a switching power supply are made to coexist, it is necessary to firmly shield the interfering source, which causes structural restrictions and cost increase. It was

The present invention is intended to solve the above-mentioned problems of the conventional example, and to construct an interference source such as a switching power source without shielding the surroundings with an expensive sheet metal and without structural restrictions. , The AM loop antenna main body and the interference source are separated from each other by distance, so that the digitization of a switching power supply or the like can be inexpensively incorporated into a receiving device having an AM receiving circuit using the AM loop antenna.

[0006]

In order to achieve the above object, an AM loop antenna device of the present invention is connected to a tuner which is included in a main body of a receiving device and is capable of receiving the AM band, and the tuner which is connected to the tuner via a connecting cable. AM loop antenna,
A receiver provided with a noise generation source that generates radiation noise in the same housing of the reception device main body as the tuner, wherein the noise generation source is a harmonic of a multiple of one digit of the frequency of the radiation noise. The waves generate radiation noise corresponding to the frequency of the reception frequency band of the AM tuner, and the AM loop antenna includes an AM loop antenna body having a copper wire wound several turns and an antenna of the AM tuner. A connection cable for connecting to a circuit, the connection cable having a size capable of holding a predetermined distance from the receiving device main body so that the AM loop antenna main body is not affected by the radiation noise of the noise generating source, and The outer skin is composed of a two-core shielded wire with a copper shield, and the copper shield of the connection cable takes in radiation noise from the noise source. In those constructed as to flow out to the ground portion having a receiving apparatus main body.

With the above structure, if the copper shield connection portion of the connection cable is connected to the chassis ground of the receiver main body, when radiation noise is generated from the noise source inside the receiver, the AM loop antenna main body Since the noise radiation radiated to the connection cable, which is usually a problem, falls to the chassis ground of the receiving device through the copper shield of the skin by keeping sufficiently away from the receiving device, the reception of the AM tuner circuit is affected. It will not be given.

According to a second aspect of the present invention, the noise source is a switching power source for supplying the power source of the entire receiving apparatus, the power source circuit can be downsized, and the shield structure can be provided. By eliminating it, the miniaturization can be made more effective.

According to a third aspect of the present invention, in the AM loop antenna, the two-core copper shield wires that are the constituent elements of the AM loop antenna are laid inside each other, and the copper shield portion of the skin of the AM loop antenna main body side is The side that is opened and connected to the AM tuner antenna circuit is configured to be connected to the chassis ground of the AM tuner device, and the signals extracted by the two cores other than the specific frequency band of the noise source are respectively It is possible to suppress the superimposed noise by canceling each other out.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a receiver having an AM loop antenna according to the present invention will be described in detail below with reference to FIG.

In FIG. 1, 1 is an AM loop antenna body in which a copper wire is wound several turns, 2 is a connection cable composed of two-core shielded shield wires, 3 is a copper shield that covers the surface of the connection cable 2, and 4 is a shield. It is a receiver body having an AM tuner 5 and a noise generation source 6. The connection cable 2 connected to the AM loop antenna body 1 is connected to the antenna circuit of the AM tuner 5 of the receiver body 4. The copper shield 3 which is a component of the antenna is open on the AM loop antenna main body side 3a, and is connected to the receiving equipment connecting side 3b via the chassis connecting portion 7 to the chassis ground 8 provided in the receiver main body 4.

Here, the AM loop antenna includes an AM loop antenna body 1, a connection cable 2, and a copper shield 3.
The AM loop antenna main body 1 can be arranged at a sufficient distance from the receiver main body 4, and the distance is such that the AM loop antenna main body 1 is not affected by the radiation noise of the noise generating source 6. The size is such that a predetermined distance from can be maintained. That is, the harmonic noise radiated from the noise generation source 6 jumps into the AM loop antenna main body 1 and the connection cable 2 and tries to give reception interference to the reception signal from the antenna circuit of the AM tuner 5. Is generally inversely proportional to the square of the distance,
Placing the AM loop antenna body 1 away from the receiver body 4 does not affect it. In addition, A of the receiver body 4
The connection cable 2 having a connection part with the antenna circuit of the M tuner 5 has its outer skin shielded by the copper shield 3, so that the radiated noise taken in was connected to the connection part 7 through the copper shield 3 of the outer skin. By dropping to the chassis ground 8 provided inside the receiver main body 4, reception of the AM tuner 5 is not affected.

Further, in the above-mentioned noise generation source 6, the harmonics having a multiple of one digit of the frequency of the radiation noise have a frequency (522 KHz to 16) in the reception frequency band of the AM tuner.
29 KHz), and more specifically, it is a switching power supply for supplying power to the entire receiving device. Due to fluctuations in the power, for example, the frequency of generated noise is "40 KHz". ~ 200
KHz ", and its generation frequency has a particularly large influence 1
Higher harmonics (for example, 3 to 9 times) are in the AM frequency band “5
It is in the range of 22 kHz to 1629 kHz and becomes an interference noise. Although the switching power supply serves as such a noise generation source 6, it is necessary to completely cover this block with a shield device made of a metal plate in order to reliably prevent generation of radiation noise of the switching power supply. However, this is against the purpose of reducing the thickness of the entire receiver body 4.

In the example of the present embodiment, the receiver 4 as a whole is aimed at making the receiver main body 4 thin while
Noise source 6 that generates radiation noise inside the housing
And the radiation noise is not taken into the AM tuner 5 via the AM loop antenna without shielding the noise generation source 6. That is, by changing the connection cable to the AM loop antenna main body to an inexpensive shield type, there is no structural restriction such as surrounding the interference source of the set main body with an expensive shield box, and the digital signal of the AV receiver including the AM receiving circuit It is possible to reduce the size and thickness of the entire device.

[0015]

As described above, the receiving apparatus of the present invention has a tuner which is included in the receiving apparatus main body and is capable of receiving the AM band, and an AM which is connected to the tuner through a connecting cable.
A receiving device comprising a loop antenna and a noise generation source that generates radiation noise in the same housing of the receiving device main body as the tuner, wherein the noise generation source is one digit of the frequency of the radiation noise. Harmonics that are multiples of
Radiation noise corresponding to the frequency of the reception frequency band of the tuner is generated, and the AM loop antenna is a connection for connecting the AM loop antenna main body in which a copper wire is wound several turns and the antenna circuit of the AM tuner. The connection cable comprises a cable having a size capable of holding a predetermined distance from the receiver main body so that the AM loop antenna main body is not affected by the radiation noise of the noise generating source, and has a skin portion made of copper. It consists of shielded 2-core shielded wire, and the copper shield of the connection cable is
It is configured to capture the radiated noise of the noise source and to flow it out to the ground part of the receiving device body.If the copper shield connection part of the connection cable is connected to the chassis ground of the receiving device body, If radiation noise is generated from the noise source inside the equipment, AM
By keeping the loop antenna main body sufficiently away from the receiving device, the interference noise radiated to the connection cable, which is usually a problem, falls to the chassis ground of the receiving device through the copper shield of the skin, so the reception of the AM tuner circuit It does not affect the performance of the AM receiver circuit and the noise generation source efficiently and inexpensively, without the need for shielding the noise generation source in the main body of the receiving device, which is conventionally required, and minimizing the configuration. It is possible to provide a receiving device in which the digital electronic circuit as described above can coexist.

[Brief description of drawings]

FIG. 1 is a block diagram of a receiving device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional receiving device.

[Explanation of symbols]

1 AM loop antenna body 2 connection cable 3 Copper shield 4 Receiver body 5 AM tuner 6 noise sources 7 Copper shield connection 8 chassis ground

Claims (3)

[Claims] 1. A tuner, which is included in the receiving device main body and is capable of receiving an AM band, an AM loop antenna connected to the tuner via a connection cable, and a tuner in the same housing of the receiving device main body as the tuner. A receiving device comprising a noise generation source that generates radiation noise, wherein the noise generation source has a harmonic of a single digit multiple of the frequency of the radiation noise in a frequency of a reception frequency band of the AM tuner. Corresponding radiation noise is generated, and the AM loop antenna is an AM in which a copper wire is wound several turns.
It comprises a loop antenna body and a connection cable for connecting to the antenna circuit of the AM tuner. The connection cable is provided from the main body of the receiving device so that the AM loop antenna body is not affected by the radiation noise of the noise source. A grounding wire which has a size capable of holding a distance and is composed of a two-core shielded wire whose skin is copper-shielded, wherein the copper shield of the connection cable has radiated noise of the noise generation source and is included in the receiver main body. Receiving device characterized in that it is made to flow out 2. The receiving device according to claim 1, wherein the noise generating source is a switching power supply for supplying power to the entire receiving device. 3. In the AM loop antenna, the two-core copper shielded wires which are its constituent elements are internally biased toward each other, and the copper shield portion of the skin of the AM loop antenna main body side is opened, and an AM tuner antenna circuit is provided. The receiving device according to claim 1, wherein the connected side is configured to be connected to the chassis ground of the AM tuner device.