JPH0963850A - Noise eliminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate high frequency noise generated from a portable telephone in an existing telephone or a telephone exchange. SOLUTION: A choke coil 15 is provided at a part for connecting a telephone body 1, a telephone exchange, a handset 10, etc. The choke coil 15 has stray capacitance of 0.3pF or less and removes high frequency noise of about 1GHz or above.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a noise removing device,
In particular, it relates to a noise removing device for eliminating the adverse effect of high frequency noise on a general stationary telephone or a telephone exchange.

[0002]

2. Description of the Related Art In recent years, the spread of mobile telephones has begun to exert an adverse effect that noise is mixed in existing stationary telephones and telephone exchanges. This is because the mobile phone operates at a frequency of 800 MHz or higher (particularly 800 MHz to 2.5 GHz), and this high frequency is mixed as noise into an existing phone or telephone exchange through a line cable or the like.
Common mode choke coils are installed in existing telephones and telephone exchanges as a measure against noise, but measures against high frequencies such as those generated by mobile phones are not considered.

[0003]

Since the choke coil which has been conventionally used has a large number of turns or is wound repeatedly, it has a large stray capacitance between lines, for example, there is a stray capacitance of about 5 pF and 1 GHz. The impedance was 50 Ω or less, and high frequency noise could not be removed.

Therefore, an object of the present invention is to provide a noise eliminator capable of effectively eliminating high frequency noise of about 1 GHz or more in an existing telephone or telephone exchange.

[0005]

In order to achieve the above object, a noise removing device according to the present invention is provided with a telephone main body or a connecting portion between a telephone exchange and an external line, or a connecting portion between a telephone exchange and a telephone main body, Alternatively, a high frequency noise removing coil having a stray capacitance of 0.3 pF or less is provided at a connection portion between the telephone body and the handset. In particular, it is preferable to provide a high frequency noise removing coil at the connecting portion between the telephone body and the handset, on the side of the transmitter of the handset, and at the output of the side of the transmitter.

A coil having a small stray capacitance is formed by winding a wire into a single layer, winding it with a gap, or bobbin and core having a low dielectric constant material such as epoxy resin, ferrite, alumina, and dielectric ceramic, particularly ε. Can be obtained by a method such as forming a material of 10 or less, or not providing an exterior resin.

[0007]

[Operation] 1 GHz if the stray capacitance is 0.3 pF or less
It is possible to obtain an impedance of 500 Ω or more with respect to the high frequency, and to exert a large noise removing effect.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a noise removing device according to the present invention will be described below with reference to the accompanying drawings.
In each embodiment, the same components and the same portions are denoted by the same reference numerals. [First Embodiment, FIGS. 1 to 3] In FIG. 1, reference numeral 1 denotes a stationary telephone main body in which a circuit board 2 having a predetermined circuit mounted therein is housed. 10 is a handset.
The circuit board 2 is connected to the external line 5 at the terminal 3 and is connected to the signal line 6 of the handset 10 at the terminal 4.

A choke coil 15 is inserted on the circuit board 2 between the external line 5 and the signal line 6 and the terminals 3 and 4. The choke coil 15 is, for example, as shown in FIG.
Has the configuration shown in FIG. That is, the alumina core 16
The wire 17 is wound in a single layer with a gap, and one end of the wire 17 is connected to the electrode 18a and the other end is connected to the electrode 18b.
Connected to.

Since the choke coil 15 is a single layer and has a gap (space winding), the stray capacitance between lines is small, and the core 16 is made of alumina having an ε of 10 or less (low dielectric constant). Therefore, the stray capacitance between the electrodes 18a and 18b becomes 0.3 pF or less,
It is possible to remove high frequency noise of about 1 GHz or more that is mixed through the external line 5 and the signal line 6. Electrode 18a,
It is best that the stray capacitance between 18b is zero,
In reality, it is impossible to make it zero, and 0.1 to 0.
2 pF is better.

The stray capacitance can be reduced by adopting either single layer winding or space winding. Further, the stray capacitance between the electrodes 18a and 18b is also reduced by setting the distance between the electrodes 18a and 18b as wide as possible. In addition, as shown in FIG.
By forming the ground electrode 19 between a and 18b, the stray capacitance is further reduced.

In addition to the measures described above, when the wire 17 is wound around a resin bobbin instead of the core 16, the stray capacitance is reduced by forming the bobbin with a low dielectric constant material such as epoxy resin. May be. Further, since covering the wire 17 with a resin outer package leads to an increase in interline capacitance, it is preferable not to provide the outer package in order to reduce the stray capacitance.

[Second Embodiment, FIGS. 4 to 6] In FIG. 4, reference numeral 10 denotes a transmitter / receiver, and a receiver 11 and a transmitter 1 are provided inside.
2 are housed. The earpiece 11 is provided with a speaker, and the transmitter 12 is provided with a microphone. The earpiece 11 is connected to the stationary telephone body by a pair of signal lines 6, and the transmitter 12 is connected to the stationary telephone body by a pair of signal lines 6 via a choke coil 20.

The choke coil 20 has, for example, the configuration shown in FIG. That is, the alumina core 21 having an ε of 10 or less is composed of a winding core portion 21a, and an upper flange portion 21b and a lower flange portion 21c provided at both ends of the winding core portion 21a.
For example, the size of the core 21 is 1.8 mm in height, 3.2 mm in length, and 1.6 mm in width. The wire 22 is wound around the winding core portion 21a in a single layer, and one end of the wire 22 is connected to the electrode 23a and the other end is connected to the electrode 23b. For example, the diameter of the wire 22 is 35 μm, and the winding number is 1
Two turns. When the length of the winding core portion 21a is L, the wire diameter of the wire 22 and the number of windings are D and n, respectively, the following conditions are satisfied.

D × n ≦ L <D × (n + 1) Under this condition, when the wire 22 is wound in a single layer, the wires 22 are densely packed and wound around the winding core portion 21a in an aligned state. It is possible to prevent the subsequent winding disorder and the displacement of the wire 22 during use of the choke coil, and to prevent the resonance frequency from changing.

Further, in order to improve the high frequency noise removing capability, the resonance frequency of the choke coil 20 is set as shown in FIG.
As shown in FIG. 1, the operating frequency of the mobile phone (including PHS, etc.) is 800 to 1000 MHz or 1400 to 1500.
It is set in the range of MHz or 1900 to 2000 MHz (see solid line 25).

In the noise eliminator having the above structure, since the choke coil 20 is provided in the input / output section of the handset 10 on the side of the transmitter 12, the high frequency noise can be removed most effectively. Moreover, since the core 21 is made of alumina having ε of 10 or less (because of the low dielectric constant), the stray capacitance between the electrodes 23a and 23b is 0.3 pF.
Below, the high frequency noise can be further removed. It has been confirmed through experiments that the noise removal function is most effective when the position where the choke coil 20 is provided is set to the output section on the transmitter section 12 side of the handset 10. It is considered that when it is provided at this position, it is possible to prevent the noise that has entered the transmitting unit 12 from being detected and propagating to the signal line 6.

[Other Embodiments] The noise removing apparatus according to the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the gist thereof. The choke coil is not limited to the ones shown in the above embodiment, and may be the choke coils 30 and 35 shown in FIGS. 7 and 8, for example. The choke coils 30 and 35 are of the horizontal mounting type, and the wires 33 and 38 are wound around the alumina cores 31 and 36 in a single layer and with a gap therebetween. Each wire 33, 3
Both ends of 8 are connected to electrodes 32a, 32b, 37a, 37b.

Alternatively, the choke coil 40 shown in FIG.
As described above, in the horizontal mounting type in which the axial direction of the winding core portion 41a of the core 41 is parallel to the mounting surface 45 of the choke coil 40, the wire 43 is wound around the winding core portion 41a in a single layer with a gap. The portion of the wound wire 43 provided on the upper surface of the choke coil 40 is made of resin 44.
It may be coated with. Wire 43
Both ends of are connected to electrodes 42a and 42b. Electrode 4
2a and 42b are designed so as not to go around the mounting surface 45 of the choke coil 40 in order to suppress the stray capacitance between the electrodes 42a and 42b. Thus, the wire 4
By coating 3 with resin 44, the upper surface of the choke coil 40 can be flattened. When the choke coil 40 is mounted on a printed circuit board or the like using an automatic mounting machine, the suction chuck 45 of the automatic mounting machine can be used. The choke coil 40 can be reliably chucked.

Further, the choke coil 50 shown in FIG.
As described above, the thickness (diameter) of the winding core portion 51a of the core 51 is gradually changed to form the winding core portion 51a having an inclined surface,
The wire 53 may be wound around the inclined surface in a single layer with a gap. This choke coil 50
In the above, by winding the wire 53 around the winding core portion 51a from the small diameter side toward the large diameter side, the winding work can be performed without the wound wire 53 being displaced. Both ends of the wire 53 are connected to the electrodes 52a and 52b.

Further, as shown in FIG. 11, a groove 57 is formed on the surface of the winding core portion 56a of the core 56, and along this groove 57, as shown in FIG. By providing and winding, the wire 59 can be prevented from being displaced, and the stray capacitance can be reliably reduced. Both ends of the wire 59 are connected to the electrodes 58a and 58b.

Further, the choke coils 15, 30, 3
The position where 5 or the like is provided may be a connection portion between the telephone exchange and the external line or a connection portion between the telephone exchange and the telephone body.

[0023]

As is apparent from the above description, according to the present invention, the connecting portion between the telephone main body or the telephone exchange and the external line, or the connecting portion between the telephone exchange and the telephone main body,
Or, a high-frequency noise removal coil with a stray capacitance of 0.3 pF or less is provided at the connection between the telephone body and the handset, so high-frequency noise mixed through the external line, internal line, or the signal line code of the handset is effectively removed. can do.

In particular, if a high-frequency noise removing coil is provided at the connecting portion between the telephone body and the handset, on the side of the transmitter of the handset, and at the output of the side of the transmitter, high-frequency noise is most effectively removed. can do. Further, if the resonance frequency of the high frequency noise removing coil is set to the frequency range used by the mobile phone, the noise removing effect will be further enhanced. Also, the length of the core of the high frequency noise removing coil or the winding core of the bobbin is L, the wire diameter of the wire is D, and the number of windings of the wire is n.
Then, by satisfying the relationship of D × n ≦ L <D × (n + 1), winding disorder after winding,
It is possible to prevent the wire from being displaced during use and to prevent the resonance frequency from fluctuating.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a telephone including a first embodiment of a noise removing device according to the present invention.

FIG. 2 is a sectional view showing an example of a choke coil used as the noise removing device shown in FIG.

FIG. 3 is a cross-sectional view showing a modified example of the choke coil shown in FIG.

FIG. 4 is a schematic explanatory diagram of a telephone equipped with a second embodiment of a noise removing device according to the present invention.

5 is a cross-sectional view showing a choke coil used as the noise removing device shown in FIG.

6 is a graph showing a resonance frequency characteristic of the choke coil shown in FIG.

FIG. 7 is a cross-sectional view showing another embodiment of the noise removing device.

FIG. 8 is a sectional view showing still another embodiment of a noise removing device.

FIG. 9 is a perspective view showing still another embodiment of the noise removing device.

FIG. 10 is a sectional view showing still another embodiment of a noise removing device.

FIG. 11 is a cross-sectional view showing still another embodiment of a noise removing device.

12 is a cross-sectional view showing a state after winding of the noise eliminator shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Telephone main body 2 ... Circuit board 5 ... External line 6 ... Signal line 10 ... Handset 15 ... Choke coil 12 ... Transmission part 20 ... Choke coil 21 ... Core 21a ... Core part 22 ... Wire 30, 35, 40, 50, 55 ... Choke coil 31, 36, 41, 51, 56 ... Core 41a, 51a, 56a ... Winding core part 43, 53, 59 ... Wire 44 ... Resin 57 ... Groove

Claims (9)

[Claims] 1. A high frequency with a stray capacitance of 0.3 pF or less in the connection part between the telephone body or the telephone exchange and the external line, the connection portion between the telephone exchange and the telephone body, or the connection portion between the telephone body and the handset. A noise removing device comprising a noise removing coil. 2. The noise removing apparatus according to claim 1, wherein a material having an ε of 10 or less is used for the core or the bobbin of the high frequency noise removing coil. 3. The noise removing device according to claim 1, wherein the high frequency noise removing coil is provided at a connecting portion between the telephone body and the handset and on a side of a transmitter of the handset. 4. The noise according to claim 1, wherein the high-frequency noise removing coil is provided at a connecting portion between the telephone body and the handset and at an output section of the handset side of the handset. Removal device. 5. The noise eliminator according to claim 1, wherein a resonance frequency of the high frequency noise eliminator coil is set in a frequency range used by the mobile phone. 6. A core of the high frequency noise removing coil or a winding core of a bobbin has an inclined surface, and a wire is wound on the inclined surface in a single layer with a gap. Item 1. A noise removing device according to item 1. 7. A groove is provided on a surface of a winding core of a core of the high frequency noise removing coil or a bobbin, and a wire is wound along the groove on the surface of the winding core in a single layer and with a gap. The noise eliminator according to claim 1, characterized in that. 8. A wire is wound in a single layer on the surface of the core of the high frequency noise removing coil or the core of the bobbin, and the length of the core of the core or the bobbin is L and the wire diameter of the wire is D. The noise elimination device according to claim 1, wherein the relation of D × n ≦ L <D × (n + 1) is satisfied, where n is the number of windings of the wire. 9. The core of the high frequency noise removing coil or the axial direction of the winding core of the bobbin is parallel to the mounting surface of the high frequency noise removing coil, and a wire is wound around the surface of the winding core. 2. The noise removing device according to claim 1, wherein at least a portion of the wound wire, which is provided on the upper surface of the high frequency noise removing coil, is coated with resin.