JP2005203821A - Antenna feeding line for am reception and noise eliminating part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna feeding line for AM reception having no problem in fault due to noises imposing on an AM receiver, even if it is bundled together with a wire harness when being installed in a vehicle. <P>SOLUTION: The antenna feeding line 1 for AM reception has an electric wire main section 3 consisting of a center conductor and an external conductor provided on the outer periphery of an insulator layer provided on the outer periphery of the center conductor, and couples an AM receiver to an antenna for AM reception to transmit signals received by the antenna for AM reception to the AM receiver. The feeding line 1 is provided with a noise eliminator 8 near an antenna jack 2 forming a connection portion to the AM receiver. The eliminator 8 is configured so as to have a magnetic core 13, a first coil 15 formed by winding a winding wire around the magnetic core 13 and electrically coupled to the center conductor, and a second coil 16 formed by winding a winding wire around the magnetic core 13 so as to be in-phase winding with the first coil 15 and electrically coupled to the external conductor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an AM receiving antenna feed line for connecting an AM receiver and an AM receiving antenna, and a noise removing component provided in the AM receiving antenna feed line.

  As an AM receiving antenna feed line for connecting an AM receiver and an AM receiving antenna, a coaxial cable having a one-layer shield structure in which one shield layer is provided on the outer periphery of an insulator layer provided on the outer periphery of a central conductor, The first shield layer is provided on the outer periphery of the first insulator layer provided on the outer periphery of the central conductor, and the second shield layer is provided on the outer periphery of the second insulator layer provided on the outer periphery of the first shield layer. A coaxial cable having a two-layer shield structure provided with a cable is known (for example, see Patent Documents 1 and 2).

  Conventionally, when routing these AM receiving antenna feeders to a vehicle, it is common to separate the wire harness from the wire harness and create a separate route (see, for example, Patent Document 3).

This is because the in-vehicle AM receiver has a high antenna input impedance, so the AM receiving antenna feeder line is easy to pick up noise, and when it is bundled with a wire harness and wired together, various types of switching generated in the vehicle This is because noise rides on the AM receiving antenna feed line via the wire harness.
JP 2000-48653 A JP 2003-59349 A JP-A-8-140239

  However, as described above, it is inefficient to lay out the AM receiving antenna feeder line through a separate path from the wire harness, and the efficiency is low in assembling the wire harness. Therefore, it is desirable to bundle the AM receiving antenna feeding line and the wire harness together and route them in the same route.

  When the AM receiving antenna power supply line is bundled together with the wire harness, it is necessary to use an AM receiving antenna power supply line having a larger noise attenuation effect than the conventional one. However, the shielding effect of the conventional coaxial cable having the one-layer shield structure and the coaxial cable having the two-layer shield structure does not have an effect sufficient to attenuate noise when bundled together with the wire harness.

  The object of the present invention is that the noise attenuation effect of the signal received by the AM receiving antenna and input to the AM receiver is large, and the noise given to the AM receiver even when bundled with the wire harness when routed in a vehicle. An object of the present invention is to provide an AM receiving antenna feed line that has no problem in terms of obstacles, and a noise removal component provided in the AM receiving antenna feed line.

  In order to solve the above-mentioned problem, the invention according to claim 1 is an AM receiving apparatus for connecting an AM receiver and an AM receiving antenna and transmitting a signal received by the AM receiving antenna to the AM receiver. The antenna feeder is characterized in that a noise removal unit is provided in the vicinity of the connection with the AM receiver or in the vicinity of the connection.

  The invention according to claim 2 includes an electric wire main body configured to include a central conductor and an outer conductor provided on an outer periphery of an insulator layer provided on an outer periphery of the central conductor, and an AM receiver. In an AM receiving antenna feed line that connects an AM receiving antenna and transmits a signal received by the AM receiving antenna to the AM receiver, noise is present at or near the connection to the AM receiver. A removal portion is provided, and the noise removal portion is formed on the magnetic core, a first coil formed by winding the magnetic core and electrically connected to the central conductor, and the magnetic core. And a second coil that is formed by winding so as to be in-phase with the first coil and is electrically connected to the outer conductor.

  The invention described in claim 3 has an electric wire main body configured to include a central conductor and an outer conductor provided on the outer periphery of an insulator layer provided on the outer periphery of the central conductor, and an AM receiver. In an AM receiving antenna feed line for connecting an AM receiving antenna and transmitting a signal received by the AM receiving antenna to the AM receiver, a noise removing unit is provided in the vicinity of the connecting portion with the AM receiver. The noise removing portion is formed by winding a part of the electric wire main body around a magnetic core.

  According to a fourth aspect of the present invention, the magnetic core according to the first, second, or third aspect has a magnetic permeability of 5000 or more.

  According to a fifth aspect of the present invention, an AM receiver and an AM receiver having an electric wire main body portion including a central conductor and an outer conductor provided on the outer periphery of an insulator layer provided on the outer periphery of the central conductor Connected to a receiving antenna and connected to the AM receiver in an AM receiving antenna feed line for transmitting a signal received by the AM receiving antenna to the AM receiver, or in the vicinity of the connecting portion, A magnetic core, a first coil formed by winding the magnetic core and electrically connected to the central conductor, and a winding wound in the same phase as the first coil on the magnetic core And a second coil electrically connected to the outer conductor.

  According to a sixth aspect of the present invention, an AM receiver and an AM receiver having an electric wire main body portion including a center conductor and an outer conductor provided on the outer periphery of an insulator layer provided on the outer periphery of the center conductor. Provided in the vicinity of the connection portion with the AM receiver in the AM receiving antenna feeder for connecting the receiving antenna and transmitting the signal received by the AM receiving antenna to the AM receiver, A portion of the wire main body of the AM receiving antenna feeder is wound around.

  The invention described in claim 7 is characterized in that the magnetic core according to claim 5 or 6 has a magnetic permeability of 5000 or more.

  According to the first aspect of the present invention, when the AM receiving antenna feed line is bundled together with the wire harness and wired in the vehicle, various switching noises generated in the vehicle are bundled together. Even if the antenna gets on the AM receiving antenna feed line via the antenna, the noise is attenuated by the noise removing section provided in the vicinity of the connecting section with the AM receiver. By such noise removal by the noise removing unit, according to the AM receiving antenna feeder line of the invention described in claim 1, even when bundled together with a wire harness when being routed in a vehicle, it is given to the AM receiver. There is no problem in terms of noise interference.

  According to the second aspect of the present invention, the first coil is formed by winding the magnetic core and is electrically connected to the central conductor, and the same coil as the first coil is wound around the magnetic core. Noise is attenuated at a portion of the second coil that is formed by winding so as to be electrically connected to the outer conductor. Thus, according to the antenna receiving wire for AM reception according to the second aspect of the present invention, there is no problem in terms of noise disturbance given to the AM receiver even if the antenna receiving wire is bundled together with the wire harness when being wired in the vehicle. .

  According to the third aspect of the present invention, the noise removing unit configured by winding a part of the electric wire main body having the center conductor and the outer conductor around the magnetic core includes the center conductor and the outer conductor. The first coil and the second coil are wound in the same phase. Since the noise is attenuated at the first coil and the second coil, the AM receiving antenna power supply line according to the third aspect of the present invention is bundled together with the wire harness when wiring to the vehicle. However, there is no problem in terms of noise interference given to the AM receiver.

  According to invention of Claim 4, since the magnetic permeability of the said magnetic body core which comprises the said noise removal part of Claim 1, 2, or 3 is 5000 or more, it is more efficient by the said noise removal part. Noise can be attenuated.

  According to the fifth aspect of the present invention, by providing the noise removing component having the above-described configuration in the vicinity of the connection portion of the antenna feeder line with the AM receiver or in the vicinity of the connection portion, the AM reception antenna receives the AM reception. A first coil that is formed by winding a magnetic core and electrically connected to the center conductor, and the magnetic core is wound in phase with the first coil. Thus, it can be attenuated at the portion of the second coil formed by winding and electrically connected to the outer conductor. As a result, there is no problem in terms of noise interference given to the AM receiver even if the AM receiving antenna power supply line provided with the noise removing component is wired together with the wire harness.

  According to the sixth aspect of the present invention, the noise removal component provided at or near the connection portion of the antenna feeder line with the AM receiver includes the central conductor and the outer conductor. By winding a part of the main body around the magnetic core, the central conductor and the outer conductor have a first coil and a second coil that are wound in the same phase. The noise of the signal received by the AM receiving antenna and input to the AM receiver can be attenuated by the first coil and the second coil. As a result, there is no problem in terms of noise interference given to the AM receiver even if the AM receiving antenna power supply line provided with the noise removing component is wired together with the wire harness.

  According to the invention described in claim 7, since the magnetic core constituting the noise removing component according to claim 5 or 6 has a magnetic permeability of 5000 or more, noise can be more efficiently generated by the noise removing component. Can be attenuated.

Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a first embodiment of an AM receiving antenna feed line and noise elimination component according to the present invention, FIG. 2 is a perspective view showing a first terminal fitting, and FIG. 3 is a plan view showing a second terminal fitting. 4 is a front view of the second terminal fitting shown in FIG. 3, FIG. 5 is a right side view of the second terminal fitting shown in FIG. 3, and FIG. 6 is an electric wire main body, the first terminal fitting, and the second terminal fitting. FIG. 7 is a right side view of FIG. 6, and FIG. 8 is a front view of FIG.

  In the figure, reference numeral 1 denotes an AM receiving antenna feed line of this example for connecting an AM receiver and an AM receiving antenna and transmitting a signal received by the AM receiving antenna to the AM receiver. This AM receiving antenna feed line 1 has an antenna jack 2 that constitutes a connecting portion connected to the AM receiver at one end, and an electric wire main body 3 whose other end is connected to the AM receiving antenna. It is comprised.

  The electric wire main body 3 includes a center conductor 4 and an insulator layer 5 provided on the outer periphery of the center conductor 4, and further includes an outer conductor formed of a copper braided wire provided on the outer periphery of the insulator layer 5. 6 and a coaxial cable having a sheath 7 provided on the outer periphery of the outer conductor 6 (see FIGS. 6 to 8). In addition, although the said external conductor 6 is comprised with the copper braided wire in this example, it is not restricted to such a thing.

  The electric wire main body 3 is provided with a noise removing component 8 inserted in a portion in the vicinity of the antenna jack 2. The noise removing component 8 constitutes a noise removing unit for attenuating noise mixed from the outside in the wire main body 3 to the signal received by the AM receiving antenna immediately before being input to the AM receiver. Yes. The electric wire main body 3 is divided into an antenna jack 2 side portion indicated by reference numeral 3a and an AM reception antenna side portion indicated by reference numeral 3b with the noise removing component 8 interposed therebetween.

  The noise removing component 8 has a box-shaped case 9 made of synthetic resin and a substrate 10 fixed in the case 9, and the substrate 10 has an electric wire main body 3a on the antenna jack 2 side and an AM. The wire body 3b on the receiving antenna side is fixed. Specifically, the end of the electric wire main body 3a on the antenna jack 2 side is inserted into the case 9 from the through hole 11 of the side wall 9a of the case 9 and fixed to the substrate 10, and the end of the AM receiving antenna side is also fixed. An end of the electric wire main body 3 b is inserted into the case 9 from the through hole 12 of the side wall 9 b of the case 9 and fixed to the substrate 10. Further, a ring-shaped magnetic core 13 is fixed to the substrate 10. In the figure, the case 9 is shown in a cross-sectional state to show the inside.

  The magnetic core 13 is made of a magnetic material having a magnetic permeability of 5000 or more, such as MzZn ferrite or amorphous permalloy. Since the magnetic core 13 is formed of such a magnetic material, noise can be more efficiently removed by a first coil and a second coil described later. The magnetic core 13 is fixed between the protrusion 14a into which the hollow portion of the magnetic core 13 is inserted and the protrusions 14b, 14c, 14d, and 14e provided around the protrusion 14a. It has become.

  The magnetic core 13 is provided with a winding that forms the first coil 15 and a winding that forms the second coil 16. The winding forming the first coil 15 and the winding forming the second coil 16 are wound so as to be in-phase with each other.

  The winding forming the first coil 15 is electrically connected to the central conductor 4 of the electric wire main body 3a on the antenna jack 2 side at one end side, and the electric wire main body 3b on the AM receiving antenna side to the other end side. The central conductor 4 is electrically connected. The winding forming the second coil 16 is electrically connected to the outer conductor 6 of the wire main body 3a on the antenna jack 2 side at one end and the wire main body on the AM receiving antenna side at the other end. The outer conductor 6 of 3b is electrically connected. Hereinafter, the connection structure of the center conductor 4 to the first coil 15 and the connection structure of the outer conductor 6 to the second coil 16 will be specifically described.

  In FIG. 2, reference numeral 17 indicates a first terminal fitting for electrically connecting the center conductor 4 to the first coil 15. The first terminal fitting 17 is formed of a metal plate and includes a substantially U-shaped portion 18 and a linear portion 19 provided integrally with the substantially U-shaped portion 18. ing.

  3 to 5, reference numeral 20 indicates a second terminal fitting for electrically connecting the outer conductor 6 to the second coil 16. The second terminal fitting 20 also serves to fix the electric wire body 3 to the substrate 10.

  The configuration of the second terminal fitting 20 will be described in detail. The second terminal fitting 20 is formed by punching a metal plate and bending it, and for crimping the external conductor 6 on the front end side thereof. A pair of outer conductor crimping pieces 21, 21 are formed from the base portion 22, and a pair of sheath crimping pieces 23, 23 for crimping the sheath 7 are raised from the base portion 22 on the rear end side. Is formed. Further, the second terminal fitting 20 has a fixing piece 24 for fixing the second terminal fitting 20 on the substrate 10 between the outer conductor crimping piece 21 and the sheath crimping piece 23, rising from the base portion 22. A lead wire connecting piece 25 is formed from the base portion 22 so as to connect to a lead wire (described later) connected to the external conductor 6.

  A connection structure between the central conductor 4 and the first coil 15 by the first terminal fitting 17 and a connection structure between the outer conductor 6 and the second coil 16 by the second terminal fitting 20 will be described with reference to FIGS. To do.

  First, a connection structure between the central conductor 4 and the first coil 15 by the first terminal fitting 17 will be described. The first terminal fitting 17 is fixed to the substrate 10. Specifically, the fixing of the first terminal fitting 17 to the substrate 10 will be described. First, the linear portion 19 of the first terminal fitting 17 is inserted into the through hole 26 provided in the substrate 10 from above. Then, the straight portion 19 penetrating the substrate 10 is bent by the first bent portion 19a, and further bent by the second bent portion 19b, and then the straight portion 19 is inserted into the through hole 27 of the substrate 10 from the lower side to the upper side. And is further bent at the third bent portion 19 c on the substrate 10. Thereby, the first terminal fitting 17 is fixed on the substrate 10. Then, the central conductor 4 is soldered to the upper surface 18a of the substantially U-shaped portion 18 of the first terminal fitting 17 fixed to the substrate 10 in this way, and the tip of the straight bent portion 19 is more distal than the third bent portion 19c. The lead wire 28 connected to the first coil 15 is soldered to the side portion (not shown in FIG. 8). Thereby, the central conductor 4 is electrically connected to the first coil 15.

  In the noise removing component 8 of this example, the first terminal fitting 17 to which the central conductor 4 of the electric wire main body 3a on the antenna jack 2 side is connected and the central conductor of the electric wire main body 3b on the AM receiving antenna side. 4 to which the first terminal fitting 17 is connected, each having the connection structure shown in FIGS. Thereby, the central conductor 4 of the electric wire main body 3a on the antenna jack 2 side and the central conductor 4 of the electric wire main body 3b on the AM receiving antenna side are electrically connected to the first coil 15.

  Next, a connection structure between the outer conductor 6 and the second coil 16 by the second terminal fitting 20 will be described. The second terminal fitting 20 is fixed to the substrate 10. The fixing of the second terminal fitting 20 to the board 10 will be specifically described. The board 10 has through holes 29a provided corresponding to the pair of external conductor crimping pieces 21 and 21 of the second terminal fitting 20, respectively. 29 b, through holes 30 a and 30 b provided corresponding to the pair of sheath crimping pieces 23 and 23, through holes 31 provided corresponding to the fixing pieces 24, and lead wire connecting pieces 25. The through-hole 32 is provided. Then, in these through holes 29a, 29b, 30a, 30b, 31, 32 of the substrate 10, outer conductor crimping pieces 21, 21 of the second terminal fitting 20, sheath crimping pieces 23, 23, fixing pieces 24, leads The line connecting piece 25 is inserted from the lower side of the substrate 10, and the fixed piece 24 and the lead wire connecting piece 25 are bent on the substrate 10. A lead wire 33 connected to the second coil 16 is connected to the lead wire connecting piece 25 by soldering. Further, the outer conductor 6 is crimped by the pair of outer conductor crimping pieces 21, 21, the sheath 7 is crimped by the pair of sheath crimping pieces 23, 23, and the electric wire body 3 is connected to the second terminal. It is fixed on the substrate 10 by a metal fitting 20. With the configuration as described above, the outer conductor 6 is electrically connected to the second coil 16.

  In the noise removing component 8 of this example, the second terminal fitting 20 to which the outer conductor 6 of the electric wire main body 3a on the antenna jack 2 side is connected and the outer conductor of the electric wire main body 3b on the AM receiving antenna side. 6 are connected to each other, and each has the connection structure shown in FIGS. 6 to 8. Thereby, the outer conductor 6 of the electric wire main body 3a on the antenna jack 2 side and the outer conductor 6 of the electric wire main body 3b on the AM receiving antenna side are electrically connected to the second coil 16.

  The noise removing component 8 configured as described above has an equivalent circuit as shown in FIG. Then, in the first coil 15 and the second coil 16, noise mixed from the outside with respect to the signal received by the AM receiving antenna and transmitted by the wire main body 3 is input to the AM receiver. It can be attenuated by removing it in the previous part. Specifically, the first coil 15 and the second coil 16 can provide a high impedance (about 690 Ω) in the frequency range of about 1000 kHz when the inductance is generated at 110 μH or more, and are received by the AM receiving antenna. The noise attenuation effect of at least 20 dB can be obtained in the range from 525 kHz to 1650 kHz, which is the corresponding frequency range of the received signal, compared with the case where the noise removal component 8 of this example is not provided, and in part, 30 dB The noise attenuation characteristic can be obtained.

  On the other hand, since the first coil 15 and the second coil 16 are wound in the same phase with each other, the impedance of the signal received by the AM receiving antenna is canceled and passes through the noise removing unit without resistance. As described above, only the noise can be removed and attenuated without affecting the received signal.

  As described above, according to the AM receiving antenna feeder 1 of this example, the noise attenuation effect when the noise removing component 8 is not provided, that is, the one-layer shield having only one outer conductor constituting the shield layer. Compared with the noise attenuation effect of the coaxial cable having the structure, at a frequency of 1 MHz, the noise attenuation effect is at least 20 dB or more (10 times noise attenuation effect), and partially has a noise attenuation effect of 30 dB (about 30). Double noise attenuation effect). When the AM receiving antenna feed line is bundled together with the wire harness and wired in the vehicle, the noise attenuation effect is more than 10 times that of the coaxial cable with the single-layer shield structure in order to reduce the noise disturbance given to the AM receiver. is necessary. Therefore, the AM receiving antenna feeder line 1 of this example has such a noise attenuation effect, and even if it is bundled with a wire harness and wired together in a vehicle, it is a point of noise disturbance given to the AM receiver. There is no problem.

  As shown in FIG. 10, the noise removing component 8 may be provided integrally with the antenna jack 2. In this case, the winding of the first coil 15 has one end connected to the central conductor 4 of the electric wire main body 3 and the other end electrically connected to the central conductor 4 among the constituent parts of the antenna jack 2. To be connected to. The winding of the second coil 16 has one end connected to the outer conductor 6 of the electric wire main body 3 and the other end connected to the portion of the antenna jack 2 where the outer conductor 6 is electrically connected. Connected.

Next, a second embodiment of the AM receiving antenna feed line and the noise removal component according to the present invention will be described with reference to FIG.
FIG. 11 is a diagram showing the AM receiving antenna feed line and the noise removal component of this example.

  In the AM receiving antenna feeder 40 of this example, the noise removing component 41 is configured to have a printed board (SMD board) 43 on which a ring-shaped magnetic core 42 is mounted. The printed circuit board 43 is fixed in the case 44. In the figure, the case 44 is shown in a cross-sectional state to show the inside.

  The magnetic core 42 is formed of a magnetic material having a magnetic permeability of 5000 or more, such as MzZn ferrite or amorphous permalloy, as in the first example of the embodiment. Further, the magnetic core 42 is wound as in the first example of the magnetic core 13 of the above-described embodiment, and a first coil and a second coil are formed (not shown). And the winding which forms a 1st coil, and the winding which forms a 2nd coil are wound so that it may become in-phase winding mutually.

  Two first terminal fittings 17 and two second terminal fittings 20 are fixed to the printed circuit board 43 in the same manner as in the first example of the embodiment, and the antenna jack 2 is connected by the second terminal fittings 20. The wire main body 3a on the side and the wire main body 3b on the AM receiving antenna side are fixed (similar to the first embodiment, the end of the wire main body 3a from the through hole 11 of the side wall 44a of the case 44) And the end of the electric wire body 3b is inserted from the through hole 12 of the side wall 44b of the case 44). Then, the conductor pattern 45 formed on the first terminal fitting 17 and the printed board 42 causes the first coil to have the central conductor 4 of the electric wire main body 3a on the antenna jack 2 side and the electric wire main body 3b on the AM receiving antenna side. The central conductor 4 is electrically connected (in this example, the lead wire 28 shown in FIGS. 6 and 7 is not provided). Also, the conductor pattern 45 formed on the second terminal fitting 20 and the printed circuit board 42 allows the second coil to have the external conductor 6 of the wire body 3a on the antenna jack 2 side and the wire body 3b on the AM receiving antenna side. The outer conductor 6 is electrically connected (in this example, the lead wire 33 shown in FIGS. 6 and 7 is not provided). As a result, the noise removal component 41 of the present example forms the equivalent circuit shown in FIG. 9 as in the first example of the embodiment.

The noise elimination component 41 configured in this way is provided in the vicinity of the antenna jack 2 as in the first example of the embodiment. However, it may be provided integrally with the antenna jack 2 as in the first example of the embodiment.
According to the AM receiving antenna feed line 40 and the noise removal component 41 of the present example described above, the same operation and effect as the first example of the above embodiment are provided.

Next, a third embodiment of the AM receiving antenna feed line and the noise removing component according to the present invention will be described with reference to FIG.
The AM receiving antenna feeder 50 of this example is provided with a noise removing component 51 in the vicinity of the antenna jack 2. In the noise removing component 51, a part of the electric wire main body 3 is wound around the ring-shaped magnetic core 52. After the electric wire main body 3 is wound around the magnetic core 52 in this manner, the electric wire main body 3 is wound. It is comprised by winding the adhesive tape 53 so that it may not be unwound.

  The magnetic core 52 is formed of a magnetic material having a magnetic permeability of 5000 or more, such as MzZn-based ferrite or amorphous permalloy, as in the first example of the embodiment.

  In this example, the first coil 15 and the second coil 16 are formed by winding a part of the electric wire main body 3 around the magnetic core 52. More specifically, the first coil 15 is formed by the central conductor 4 of the wire main body 3 wound around the magnetic core 52. Further, the second coil is formed by the outer conductor 6 of the electric wire main body 3 wound around the magnetic core 52. The first coil 15 and the second coil 16 formed in this way also have the electric wire body 3 having the central conductor 4 forming the first coil 15 and the outer conductor 6 forming the second coil 16 as a magnetic material. Winding around the core 52 inevitably results in in-phase winding.

  The noise removal component 51 having the above configuration also has the equivalent circuit shown in FIG. 9 as in the first example of the embodiment.

  According to the AM receiving antenna feed line 50 and the noise removing component 51 of the present example described above, the same operations and effects as those of the first example of the above embodiment are provided.

Next, a fourth embodiment of the AM receiving antenna feed line and the noise removal component according to the present invention will be described with reference to FIG.
The AM receiving antenna feeder 60 of this example is provided with a noise removing component 61 in the vicinity of an antenna jack not shown in FIG. The noise removing component 61 is configured by winding the electric wire body 3 around a clamp core 62 (corresponding to a magnetic core in claims) configured to be separable.

  The clamp core 62 is formed of a magnetic material having a magnetic permeability of 5000 or more, such as MzZn-based ferrite or amorphous permalloy, as in the first example of the embodiment.

  In this example, the first coil 15 and the second coil 16 are formed by winding a part of the electric wire main body 3 around the clamp core 62. As in the third embodiment, the first coil 15 is formed by the central conductor 4 of the electric wire main body 3 wound around the magnetic core 62, and the second coil 16 is formed in the third embodiment. Similar to the embodiment, the outer conductor 6 of the electric wire main body 3 wound around the magnetic core 62 is formed. In addition, the first coil 15 and the second coil 16 formed in this way are also the central conductor 4 that forms the first coil 15 and the external that forms the second coil 16, as in the third embodiment. By winding the electric wire main body 3 having the conductor 6 around the magnetic core 52, the winding is necessarily in-phase.

  The noise elimination component 61 having the above configuration also has an equivalent circuit shown in FIG. 9 as in the first example of the embodiment.

  According to the AM receiving antenna feeder 60 and the noise removing component 61 of the present example described above, the same operations and effects as those of the first example of the above embodiment are provided.

  Next, regarding the noise attenuation effect of the AM receiving antenna feeder line according to the present invention described above, a conventional coaxial cable having a single shield layer having one shield layer and a conventional two layer shield structure having two shield layers This will be described in comparison with the noise attenuation effect of the coaxial cable.

  First, a measuring apparatus for measuring the noise attenuation effect will be described. FIG. 14 shows an AM receiving antenna feed line according to the present invention, a one-layer shielded coaxial cable, and a two-layer shielded coaxial cable, when these are used as antenna feed lines in an in-vehicle AM receiver. It is a figure which shows the measuring apparatus for measuring an effect.

  The measuring device 70 shown in the figure has a circuit when the AM receiving antenna feeding line and the coaxial cable are used as an antenna feeding line in an in-vehicle AM receiving apparatus, that is, a circuit equivalent to an actual in-vehicle circuit. is there.

  The measuring device 70 has a shield room 71, and a ground plane 72 formed of a conductive metal plate is provided in the shield room 71. A cable 73 to be measured is provided on the ground plane 72. Specifically, the cable 73 to be measured is provided on a highly insulating foamed plastic (for example, styrofoam) 74 having a thickness of 5 cm placed on the ground plane 72. That is, the coaxial cable 73 to be measured is provided at a height of 5 cm from the ground plane 72 through the highly insulating foamed plastic 74.

  The cable 73 to be measured has a pseudo receiver 75 connected to one end side and a pseudo antenna 76 connected to the other end side. The pseudo receiver 75 includes an active probe (41800A manufactured by Agilent) 77 and a 300Ω resistor 78, and is grounded to the ground plane 72. The pseudo antenna 76 includes a 15 pF capacitor 80 and a 30Ω resistor 81 provided in a shield box 79, and is grounded to the ground plane 72. Reference numeral 82 denotes a 50Ω termination resistor connected to the pseudo antenna 76.

  A spectrum analyzer (8591EM manufactured by HP) 85 is connected to the pseudo receiver 75 via a cable 83 and an RF preamplifier (MH648A manufactured by Anritsu Co.). The settings of the spectrum analyzer 85 are RBW (resolution bandwidth) 9 kHz, VBW (video bandwidth) 30 kHz, and Sweep Time about 33 ms.

  On the high-insulation foamed plastic 74 on the ground plane 72, a thin low-voltage electric wire 86 for automobile is provided assuming a wire harness. This thin low-voltage electric wire 86 for automobile is provided so as to run in parallel with the cable 73 to be measured in the parallel section indicated by reference numeral 87. The parallel running distance of the parallel running section 87 is 100 cm. Further, the parallel running interval between the cable 73 to be measured in the parallel running section 87 and the thin low-voltage electric wire 86 for automobile is 0 cm assuming that the wire harness and the antenna feeding line are bundled together at the time of wiring to the vehicle. It has become.

  Both ends of the thin low-voltage electric wire 86 for automobile are grounded, and a 50Ω termination resistor 88 is connected to one end. A power meter (E4419 manufactured by Agilent) 89 is connected to the other end of the thin-walled low-voltage electric wire 86 for automobiles. The power meter 89 is connected to a signal generator (HP, 8644A) 92 via a cable 90 and an RF-PA amplifier (broadband power amplifier) 91, and the signal from the signal generator 92 receives the signal from the signal generator 92. The thin-walled low-voltage electric wire 86 for automobile is supplied.

  The power meter 89 measures the power of the signal from the signal generator 92. The power meter 89 is provided with a bidirectional coupler (not shown), and the traveling wave power and the reflected power are separated by using the bidirectional coupler.

  When measuring the noise attenuation effect of the cable to be measured using the measuring apparatus 70 as described above, the cable 73 to be measured is connected to the pseudo receiver 75 and the pseudo antenna 76. Then, after the cable 73 to be measured is set in the measuring device 70 in this way, a high frequency signal of 100 dBμV is generated from the signal generator 92. The high-frequency signal generated from the signal generator 92 is amplified by 20 dB by the RF-PA amplifier 91, is input to the power meter 89 through the cable 90, and is further supplied to the thin low-voltage electric wire 86 for automobile. The high-frequency signal generated from the signal generator 92 is radiated from the thin-walled low-voltage electric wire 86 for automobile, and this high-frequency signal is received by the cable 73 to be measured that runs along with the thin-walled low-voltage electric wire 86 for automobile. . The high frequency signal received by the cable 73 to be measured is input to the pseudo receiver 75, further input to the RF-preamplifier 84 via the cable 83, amplified by 30 dB, and input to the spectrum analyzer 85. The frequency analysis is performed and the output voltage is measured.

Next, the result of the measurement performed by such a method will be described with reference to FIGS.
FIG. 15 is a diagram showing a spectrum analyzer measurement value (output voltage) for each measurement object, and FIG. 16 is a diagram showing a shield amount for each measurement object obtained from the measurement result.

  In the figure, reference numeral 100 is a graph showing a measurement result of the AM receiving antenna feeder line according to the present invention, and reference numeral 101 is a coaxial cable having a two-layer shield structure (1.5C-2V high-frequency coaxial cord JIS C3501 one-layer shield structure) The graph which shows the measurement result about the outer periphery of the coaxial cable of which the outer conductor was given, the code | symbol 102 shows the measurement result about the coaxial cable (1.5C-2V high frequency coaxial cord JIS C3501) of a 1 layer shield structure It is a graph.

  As can be seen from the measurement results shown in the figure, the AM receiving antenna feed line according to the present invention has the most excellent noise attenuation effect (shielding effect), and the attenuation is at least 20 dB higher than the coaxial cable having the single-layer shield structure. (Shielding amount), and the attenuation amount (shielding amount) is increased by about 30 dB in part. That is, it can be seen that the AM receiving antenna feeder line according to the present invention can reduce the noise disturbance to at least 1/10, and in part, 1/30, as compared with the coaxial cable having the single-layer shield structure. In general, when a wire harness and an antenna feeder are bundled together, an attenuation amount that is 20 dB higher than that of a coaxial cable having a single-layer shield structure, that is, a shield effect that is 10 times greater is required. It has been found that the antenna feeder sufficiently satisfies this.

  As described above, according to the AM receiving antenna feed line according to the present invention, the noise attenuation effect is higher than the conventional one, and the effect is obtained even when the antenna feed line is bundled together with the wire harness as the antenna feed line of the in-vehicle AM receiver. There is no problem in terms of noise interference to the machine. Therefore, such an AM receiving antenna feeding line according to the present invention can be used as an antenna feeding line for an in-vehicle AM receiver, and can be bundled together with a wire harness and routed to the vehicle through the same route. become.

The figure which shows 1st Embodiment of the antenna feeder for AM reception and noise removal components which concern on this invention. The perspective view which shows a 1st terminal metal fitting. The top view which shows a 2nd terminal metal fitting. The front view of the 2nd terminal metal fitting shown in FIG. The right view of the 2nd terminal metal fitting shown in FIG. The top view which shows the connection structure of an electric wire main-body part, a 1st terminal metal fitting, and a 2nd terminal metal fitting. The right view of FIG. The front view of FIG. The figure which shows the equivalent circuit of the antenna feeder for AM reception which concerns on this invention. The figure which shows the modification of the antenna feed line for AM reception shown in FIG. The figure which shows 2nd Embodiment of the antenna feeder for AM reception and noise removal components which concern on this invention. The figure which shows 3rd Embodiment of the antenna feeder for AM reception and noise removal components which concern on this invention. The figure which shows 4th Embodiment of the antenna feeder for AM reception and noise removal components which concern on this invention. The figure which shows the measuring apparatus for measuring a noise attenuation | damping effect. The figure which shows the measured value (output voltage) of the spectrum analyzer about each measuring object. The figure which shows the amount of shielding about each measuring object obtained from the measurement result.

Explanation of symbols

1, 40, 50, 60 AM receiving antenna feed line 2 Antenna jack 3 Electric wire main body 4 Center conductor 5 Insulator layer 6 External conductor 8, 41, 51, 61 Noise elimination component 13, 42, 52, 62 Magnetic core 15 1st coil 16 2nd coil

Claims (7)

In an AM receiving antenna feeding line for connecting an AM receiver and an AM receiving antenna and transmitting a signal received by the AM receiving antenna to the AM receiver,
An AM receiving antenna feed line, characterized in that a noise removing section is provided in the vicinity of the connecting section with the AM receiver or in the vicinity of the connecting section. An electric wire body having a central conductor and an outer conductor provided on an outer periphery of an insulator layer provided on an outer periphery of the central conductor, and connecting an AM receiver and an AM receiving antenna; In an AM receiving antenna feeder for transmitting a signal received by the AM receiving antenna to the AM receiver,
A noise removing unit is provided in the vicinity of the connecting portion with the AM receiver or the connecting portion,
The noise removing unit includes a magnetic core, a first coil formed by winding the magnetic core and electrically connected to the central conductor, and an in-phase winding of the magnetic core with the first coil. And a second coil that is formed by winding so as to be electrically connected to the outer conductor. An electric wire body having a central conductor and an outer conductor provided on an outer periphery of an insulator layer provided on an outer periphery of the central conductor, and connecting an AM receiver and an AM receiving antenna; In an AM receiving antenna feeder for transmitting a signal received by the AM receiving antenna to the AM receiver,
A noise removal unit is provided in the vicinity of the connection with the AM receiver,
The AM receiving antenna feed line, wherein the noise removing unit is configured by winding a part of the electric wire main body around a magnetic core. 4. The AM receiving antenna feed line according to claim 1, wherein the magnetic core has a magnetic permeability of 5000 or more. 5. An electric wire main body configured to include a central conductor and an outer conductor provided on an outer periphery of an insulator layer provided on an outer periphery of the central conductor; and connecting an AM receiver and an AM receiving antenna Provided at or near the connection to the AM receiver in an AM reception antenna feed line for transmitting a signal received by the AM reception antenna to the AM receiver, a magnetic core, and the magnetic core A first coil electrically connected to the central conductor, and a winding formed on the magnetic core so as to be in-phase with the first coil. A noise removing component comprising: a second coil that is electrically connected. An electric wire main body configured to include a central conductor and an outer conductor provided on an outer periphery of an insulator layer provided on an outer periphery of the central conductor; and connecting an AM receiver and an AM receiving antenna An AM receiving antenna feed line that transmits a signal received by an AM receiving antenna to the AM receiver is provided in the vicinity of a connection portion with the AM receiver, and the magnetic core has the AM receiving antenna feed line. A noise elimination component characterized by wrapping a part of the wire body. The noise removal component according to claim 5 or 6, wherein the magnetic core has a magnetic permeability of 5000 or more.

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