JPH0773250B2 - Jack for preventing leaked radio waves - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a jack for preventing leaked radio waves radiated from a communication device such as a telephone or facsimile.

(Problems to be Solved by Prior Art and Invention) In general, a device using a digital circuit (hereinafter simply referred to as a device) is apt to generate an interference radio wave of a wide frequency with respect to other devices, and therefore, a radio or a television set. This may cause a reception failure for Jiyoung etc. and is becoming a big problem.

For this reason, it is considered internationally to regulate the interference wave generated from the equipment, and CISPR (International Radio Interference Special Committee)
“The measurement method and the allowable value of the interference wave generated from the information technology equipment” was recommended by. In Japan, a voluntary regulation council on radio wave interference prevention was established, and work to confirm conformity started.

Conventionally, as a method of suppressing the interfering wave generated from the equipment, shield body or parts, insert a yoke coil into the circuit board, etc. have been used, but the cause of the interfering wave is complicated, Since various elements are generated by combining them, it is the actual situation that it is not possible to understand unless the equipment is manufactured and measured. Therefore, in the study of suppression methods up to now, it has been necessary to repeat the estimation of the cause, the extraction of the countermeasure plan, the manufacture of the equipment for which the countermeasure is taken, the actual measurement, and the evaluation. A complicated work is required for manufacturing.

(Object of the Invention) It is an object of the present invention to provide a jack capable of commonly preventing an interference wave for various devices by a simple method.

(Means for Solving Problems) The present invention clarifies an effective method for preventing an interfering wave by quantitatively elucidating the main cause of the interfering wave and the effect of the countermeasures, and also based on this result. Based on the above, it is a feature to provide a jack having a chucking function.

First, the cause of the interference wave will be described with reference to FIGS. 7 to 10 using a digital telephone as an example. FIG. 7 is a diagram showing the connection between the base set of the telephone circuit built into the digital telephone and the line terminating equipment.
Is a telephone base set, 2 is a handset, 3 is a digital telephone circuit, and 4 is a signal sent from the telephone circuit.
Line 5, 5 is an R line for receiving signals from the network, 6 is a line terminating device (hereinafter referred to as DSU) for terminating the digital circuit,
7 is a cord for connecting the base set 1 of the telephone and the DSU 6, 8 is a transmitter, 9 is a receiver, 10 is a handset cord for connecting the base set 1 and the handset 2, 11 is a power supply circuit for commercial power supply, 12 is a commercial power line. The telephone set is composed of a base set 1 and a handset 2. The base set 1 incorporating the digital telephone circuit 3 is connected to the DSU 6 via the T line 4 and the R line, and the digital telephone circuit 3 and the DSU 6 are connected.
Signals are transmitted and received between and. The T line 4 and the R line 5 are usually combined into one string 7, and thus the string 7 is a four-core line. On the other hand, handset 2
The transmitter 8 and the receiver 9 are built in the device, and the transmitter 8 and the receiver 9 are connected to the digital telephone circuit 3.
The connection between the handset 2 containing the transmitter 8 and the receiver 9 and the base set 1 containing the digital telephone circuit 3 is usually made together by one handset cord 10. The handset string 10 is a four-core wire. Also, when using commercial power supply in addition to the power supply from DSU6,
A power supply circuit 11 for commercial power supply is built in the base set 1, and is connected to a commercial power supply via a commercial power supply line 12. As described above, the machine cord 7, the handset cord 10, and the commercial power line 12 are connected and extended from the base set in which the digital telephone circuit 3 and the commercial power supply circuit 11 are built.

FIG. 8 shows a common mode chain yoke used to evaluate the suppression of interference waves, and 13 is a ring-shaped ferrite having an outer diameter of 25 mm and an inner diameter of 15 mm. The cord 7 or the handset cord 10 was wound around the ring-shaped ferrite 13 to form a common mode chain yoke.

FIG. 9 shows the common mode chain shown in FIG.
Applied to the figure, 14 is a common mode chain yoke. The common mode chain 14 was inserted near A on the cord 7 and near B on the handset cord 10.

FIG. 10 shows an example of measurement of electric field strength (hereinafter, referred to as electric field strength) of leaked radio waves radiated from a digital telephone for explaining the effect of inserting the common mode chain yoke 14, and FIG. In a), when the common mode chain yoke is not inserted, in FIG. 10B, the common mode chain yoke 14 is inserted in the machine string 7 near A in FIG. 9 and the common mode chain yoke is installed in the handset string 10. If not inserted, FIG.
String 7 near A in the figure and handset string 10 near B
This is the case where the common mode chain yoke 14 is inserted in each of the above. However, FIGS. 10 (a) to 10 (c) show only the values at five frequencies where the electric field strength is large. From this measurement example, it is possible to lower the maximum electric field strength by about 8 dBμV / m by inserting the common mode chain yoke 14 in the cord 7 (see FIGS. 10 (a) and (b)), and Furthermore, by inserting the common mode chain yoke 14 into the handset string 10, the maximum electric field strength is further increased by 5 dBμV / m.
It can be reduced to a certain degree (see FIGS. 10 (b) and 10 (c)). The above measurement results can be explained as follows.

The cause of the interfering wave is that the measurement of the electric field strength in the vicinity of the circuit board revealed that there were several places where the electric field strength was large. Therefore, noise was generated on the circuit board, and the noise was generated by the cord 7 or transmission / reception. It is transmitted to the device cord 10, and the leaked radio wave of the interfering wave is radiated to the outside using the device cord 7 or the handset cord 10 as an antenna. Therefore, when the common mode chain yoke 14 is inserted into the cord 7 or the handset cord 10, if the current flows between the ferrite 13 and the cord 7 or the handheld cord 10 wound around the ferrite 13, the reverse occurs. High-frequency noise is reduced by the action of the chain yoke that produces electromotive force, and thus the electric field strength of the leaked radio waves radiated from the machine cord 7 and the handset cord 10 is reduced.

Based on the above measurement results and examination results, in order to suppress the interfering waves generated from the device, a chiyoke action is applied to the connection part of the conductor that exhibits the antenna action, such as a machine string or a handset string that is connected and extended outside the device. It was found that this can be achieved by inserting the chain yoke. Therefore, based on these results, the present invention realizes a jack for preventing leaked radio waves.

That is, the present invention inserts a chain yoke having a chain action for a frequency higher than that of a control signal or an information signal between a contact portion of a jack which contacts a pin of a plug and a terminal portion which is connected to a circuit board. The present invention is based on a leaky electric wave preventing jack characterized by being integrated with a jack frame, and an embodiment will be described below with reference to the drawings. Needless to say, the embodiment is merely an example, and various modifications or improvements can be made without departing from the spirit of the present invention.

FIG. 1 is a diagram showing a basic form in which a common mode yoke is inserted into a jack for connecting the machine string 7 or the handset string 10, 15 is a jack, 16 is a terminal of the machine string 7 or the handset string 10. Contact part that comes into contact with the pin of the provided plug,
Reference numeral 17 is a terminal portion connected to the circuit board. In order to reduce the electric field strength, it is only necessary to convey the noise generated on the circuit board to the cord 7 and the handset cord 10 as shown in FIGS. 10 (b) and (c). On the other hand, in order to rationalize the assembly of telephones, it is often the case that plugs are attached to the terminals of the machine cord 7 and the handset cord 10 and the jack 15 is provided on the base set 1. In such a case, the jack 15 is provided with a contact portion 16 that comes into contact with the pin of the plug and a terminal portion 17 that is connected to the circuit board, and the noise generated on the circuit board must be the terminal portion 17, the contact portion. It is transmitted through 16 to the cord 7 or the handset cord 10. Therefore, by inserting the common mode chuck yoke 14 between the terminal portion 17 and the contact portion 16, the same effect as in FIGS. 10B and 10C can be obtained. In addition, although the ferrite having the shape shown in FIG. 8 was used in the measurement of FIG.
The same effect can be obtained by using 14 rectangular magnetic bodies. Even if a ring-shaped ferrite having an outer circumference of 13 mm and an inner circumference of 6 mm is used, the same effect can be obtained if the number of windings of the string is set to about 10.

FIG. 2 is a first embodiment of a jack capable of suppressing leaked radio waves according to the present invention, in which 18 is a frame of the jack 15,
Reference numeral 19 is a claw, 20 is a magnetic material, and 21 is a code (four cores in the embodiment). The contact portion 16 and the terminal portion 17 are incorporated in the frame 18, and the claw 19 is integrated with the frame 18. The contact portion 16 and the terminal portion 17 are not shown. A cord 21 is wound around the magnetic body 20 to form a yoke, one end of the cord 21 is connected to the contact portion 16, and the other end is connected to the terminal portion 17. By inserting the magnetic body 20 into the claw 19, the frame 18 and the yoke are integrated. This allows
A jack in which the common mode yoke 14 is inserted between the contact portion 16 and the terminal portion 17 is formed. Note that FIG. 3 shows an example of the magnetic body 20 and the cord 21, and 22 is an insertion terminal. If the female portion connected to the contact portion 16 and the terminal portion 17 is provided in the frame 18 in advance, the insertion terminal 22 is inserted into the female portion when the magnetic body 20 is fitted into the frame 18, so that the assembly is rationalized. Be done. Instead of the insertion terminal 22, the contact portion 16 and the terminal portion 17 and the cord 21 may be connected by soldering, or may be connected by screwing or pressure welding.

FIG. 4 shows a second embodiment of the present invention, in which 18 'is a frame, 19' is a claw, 20 'is a claw, and 20' is a magnetic material. Nail 19 ′
Is installed on the lateral side of the frame 18 ',
The 0'can be fitted from the top side, and the back side does not have to travel.

FIG. 5 shows a third embodiment of the present invention, in which 23 is a lead wire. By connecting the lead wire 23 at the tip of the cord 21 to the circuit board, the same operation as the structure of FIG. 6 can be achieved.

FIG. 6 shows a case in which the jack of FIG. 2 is applied to a jack for a cord of an analog line telephone, and 21 'is a code. Since the cord of an analog telephone is a two-core wire, the cord 21 'is also a two-core wire.

Further, when this structure is applied to the jack for commercial power supply line of FIG. 7C, the electric field strength due to the radiation from the commercial power supply line can be suppressed, and the high frequency voltage induced at the commercial power supply terminal can be suppressed. Can be suppressed.

The present invention is different from the prior art in which the common mode chuck yoke is inserted in a place separated from the jack, and by inserting the magnetic body 20 into the frame 18 of the jack 15, the jack is inserted.
The common mode chain 14 can be integrated with the 15. For this reason, if the mounting shapes of the jacks are the same for the already manufactured printed wiring boards, the jack of the present invention capable of suppressing the electric field intensity due to radiation can be easily mounted.

(Effects of the Invention) As described above, the jack frame and the common mode choke are integrated (they are not limited to the common mode choke and may be any choke that has a choke effect for an interfering wave). Therefore, it is a controlling factor of the electric field strength of the leaked radio wave radiated outside the device only by replacing the jack necessary for connecting the cord for connecting to the line terminating device or the handset cord with the jack of the present invention. It is possible to easily suppress the radiation from the cable, eliminate the influence on radios, televisions, etc., and satisfy the standards regarding interfering waves. Further, there is an advantage that it is not necessary to remake the printed wiring board even when a problem occurs due to the interference wave. Furthermore, by using this product in various home appliances, it is possible to exert the effect of reducing the electric field strength of leaked radio waves without paying particular attention to measures against interfering waves.

On the other hand, since the magnitude of suppression of the electric field strength of the leaked radio wave radiated to the outside of the device can be changed depending on the number of turns of the cord wound around the magnetic body, in the present invention, the cord of any number of turns is wound. There is also an advantage that a magnetic material can be selected and a necessary electric field strength suppressing means can be easily obtained.

In other words, the present invention has an effect that the configuration is simple and the handling is convenient.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic form in which a common mode yoke is inserted in a jack, FIG. 2 is a perspective view of a first embodiment which best shows the features of the present invention, and FIG. 3 is a magnetic substance and a cord. FIG. 4 shows an example of the structure, FIG. 4 is a perspective view of the second embodiment of the present invention, FIG. 5 is a perspective view of the third embodiment of the present invention, and FIG. FIG. 7 is a perspective view of an embodiment when applied to a telephone, FIG. 7 is a connection diagram when operating a digital telephone, FIG. 8 is a common mode channel for evaluating interference suppression, and FIG. 9 is a common mode channel. FIGS. 10 (a), 10 (b) and 10 (c) applied to FIG. 7 are examples of measurement of electric field strength of leaked radio waves. 1 ... Base set 2 ... Handset 3 ... Digital telephone circuit 4 ... T line sending signal from telephone circuit 5 ... R line receiving signal from network 6 ... Line terminating device 7 ... Machine string 8 ... … Transmitter 9 …… Receiver 10 …… Transmitter string 11 …… Commercial power supply power supply circuit 12 …… Commercial power supply line 13 …… Ring-shaped ferrite 14 …… Common mode chain yoke 15 …… Jack 16 …… Plug Contact part that comes into contact with the pin of 17 ... Terminal part connected to the circuit board 18,18 '... Jack frame 19,19' ... Claw 20,20 '... Magnetic material 21,21' ... Code 22 ...... Insertion terminal 23 ... Lead wire

Claims (1)

[Claims] 1. A choke having a choke effect for frequencies higher than that of a control signal or an information signal is provided between a contact portion of a jack that contacts a pin of a plug and a terminal portion that contacts a circuit board. A jack for preventing leakage of radio waves, characterized in that the cords to be formed are inserted in series, and a magnetic body forming a part of the choke is fixed to the frame of the jack so as to be integrated.