JP2004080119A - Method for demagnetizing high frequency branching/distributing circuit, and method for manufacturing high-frequency apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency branching/distributing circuit which has a small strain component generated in an up signal band even by connecting to a multi-channel high output amplifier like a bidirectional CATV amplifier and to provide a method for demagnetizing a high-frequency apparatus having the branching/distributing circuit. <P>SOLUTION: When the high-frequency branching/distributing circuit having a transformer obtained by winding a lead on a ferrite is connected to the multi-channel high output amplifier like the bidirectional CATV amplifier, magnetization of the ferrite becomes a cause for generating the strain. In order to demagnetize the ferrite by stabilizing the magnetizing of the ferrite, the ferrite is demagnetized by using a demagnetizer after a soldering work of a component of the branching/distributing circuit and a mounting work of a printed circuit board are completed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branch / distribution circuit having a transformer made of ferrite mainly used for branching or distributing a high-frequency signal. The present invention relates to a method for manufacturing an electronic device having the same.
[0002]
[Prior art]
In recent years, in a CATV system, not only a signal in the VHF / UHF band or an upstream signal is transmitted, but also a wider band (for example, corresponding to 10 to 2150 MHz) including an intermediate frequency band of BS broadcasting and 110 ° CS broadcasting has been made. On the other hand, in a high-frequency branching / distribution circuit provided with a transformer formed by winding a conductive wire around a ferrite, the ferrite has been downsized and the magnetic material has been improved in order to cope with this wider band.
However, when the conventional high frequency branch / distribution circuit is connected to a bidirectional CATV amplifier and used due to the increase in the number of channels and the high output of the amplifier accompanying the broadband, the transformer provided in the high frequency branch / distribution circuit is required. Distortion components are generated in the formed ferrite, and among these distortion components, a distortion component in an upstream transmission frequency band becomes upstream inflow noise and causes a problem that a CATV center device is disturbed.
[0003]
Since this problem is caused by the fact that the ferrite is slightly magnetized, as a countermeasure, the ferrite is demagnetized by heat treatment at a temperature slightly higher than the Curie temperature specific to the ferrite. A method of assembling a high-frequency branching / distribution circuit using a transformer by winding a wire around the wire, or assembling a transformer with a wire wound around ferrite, and then using a degausser A method of assembling the high-frequency branching / distributing circuit after demagnetizing the circuit has been considered.
[0004]
[Problems to be solved by the invention]
However, in the conventional demagnetization method by heat treatment of ferrite, handling of the ferrite after heat treatment, a tool (for example, tweezers, etc.) used when winding a conductor, or soldering for electrically connecting each component. The ferrite may be re-magnetized during the work, or when the assembled printed wiring board is screwed to the case with screws, etc., and it takes time for the heat treatment in the process control. However, there has been a problem that the unit cost of parts is also high.
Also, in the method of assembling each of the transformers after demagnetizing them with a demagnetizer, the aforementioned ferrite is magnetized by a tool (for example, tweezers, a soldering iron, a driver, etc.) used in assembling the transformer. It has the same problem as the method, and at present it is very difficult to control the process for stable assembly.
Therefore, the invention of the present application has been made in view of such problems.
The purpose is to provide a branching / distributing circuit for high frequencies.
Another object of the present invention is to provide a high-frequency branching / distributing circuit including a transformer formed by winding a conductive wire around a ferrite.
It is another object of the present invention to provide a high-frequency branching / distributing circuit including a transformer in which a conductive wire is wound around ferrite with less distortion.
Another object is to provide a method for demagnetizing the ferrite.
Another object is to provide a procedure for the method of demagnetizing said ferrite.
Another object of the present invention is to provide a method of manufacturing a high-frequency device including the high-frequency branch / distribution circuit.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is a high-frequency branching / distribution circuit including a transformer formed by winding a conductive wire around a ferrite.
After the soldering of the components of the high frequency branching / distributing circuit and the mounting of the printed wiring board are completed, the ferrite is demagnetized.
[0006]
According to a second aspect of the present invention, there is provided a method for manufacturing a high-frequency device including the high-frequency branch / distribution circuit,
After the work of soldering the components of the high-frequency device and the work of mounting the printed wiring board are completed, the ferrite is demagnetized.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram of a CATV system in which a branching device / distributor according to the present invention is used. 1 is a head-end device, 2 is a transmission line, 3 is a main line amplifier, 4 is a main line distribution amplifier, and 5 is a main line branching amplifier. Amplifier, 6 tap-off, 7 is a security device, 8 is a drop-in line, 9 is a high-output bidirectional amplifier, 10 is a distributor, 11 is a branching device, 12 is a set-top box, 13 is a TV receiver, 14 is a personal computer, Reference numeral 15 denotes a high-frequency modem.
[0008]
Next, a method of manufacturing the distributor 10 employing the present invention will be described in detail with reference to FIGS.
FIG. 2A is an explanatory view of assembling the distributor, and FIG. 2B is a circuit diagram of the distributor shown in FIG. 2A.
Reference numeral 10a denotes a case, which is formed of a metal material having good conductivity, for example, zinc die-cast or aluminum die-cast. An input terminal 10b and output terminals 10c and 10d are integrally formed with the case 10a. 10e is a printed wiring board on which a distribution circuit is formed, and 10f is a lid formed of a metal having good conductivity.
First, a distribution transformer 20, a matching transformer 21, and a current passing coil 22 for passing a power supply current from an output terminal 10c or 10d at one end to an input terminal 10b, which are necessary for forming a distribution circuit on the printed wiring board 10e, are provided. In addition, a capacitor C for preventing the passage of a low-frequency current or a direct current or for correcting a frequency is mounted. Here, the distribution transformer 20 and the matching transformer 21 use a closed magnetic type ferrite core 23 through which a signal in a transmission frequency band can pass without being attenuated. An insulated wire is wound around the ferrite core 23 a required number of times. . As the ferrite core 23, for example, a DL / QM / KP series manufactured by Hitachi Ferrite Co., Ltd. is used. The ferrite used in the present invention belongs to, for example, a Ni-Zn-based or Ni-Cu-Zn-based ferrite, and a ferrite having a small loss (tan σ / μi) at a high frequency is used. Further, the material of the ferrite is not limited to this, and is appropriately selected according to the transmission frequency.
Next, the printed wiring board 10e after the soldering operation is mounted on the case 10, and the input terminals 10b and the output terminals 10c and 10d are electrically connected by soldering or the like.
Thereafter, before mounting the lid 10f, the ferrite core 23 (more specifically, the distribution transformer 20 and the matching transformer 21) is demagnetized by the procedure shown in FIG. As shown in FIG. 3, the action part 31 of the degausser 30 is brought close to the position close to the ferrite core, the power switch 32 for operation of the degausser 30 is turned on, and the operating state is set. The operating part 31 of the degausser 30 is gradually moved away from the ferrite core while keeping it at a predetermined distance (for example, 30 cm) at which the degausser 30 does not work, and then the operation power switch 32 of the degausser 30 is turned off. , Inactive. This completes the demagnetization of the ferrite.
After the demagnetization of the ferrite is completed, the lid 10f is mounted on the case 10a, and the distributor is completed.
[0009]
Next, the operation state will be described in detail.
The head end 1 is provided with a terrestrial television broadcast receiver, a satellite broadcast receiver, and various communication devices (communication control devices, transmission devices, various servers, and the like) for communicating with the outside such as the Internet. The television broadcast signal received by each receiving device and the downlink data signal from the communication device are respectively converted into downlink transmission signals (for example, 70 MHz to 770 MHz) that do not overlap in frequency, and are converted via the transmission line 2 to the downstream side. Is output to The downstream transmission signal is amplified to a predetermined level by each of the main line amplifier 3, the main line distribution amplifier 4, and the main line branch amplifier 5, and is drawn into the facility in the building via the tap-off 6, the protector 7, and the drop-in line 8.
The downstream transmission signal drawn into the premises is amplified to a predetermined level by the high-power amplifier 9 and input to the distributor 10. Since the distribution transformer 20 and the matching transformer 21 constituting the distributor 10 are demagnetized, no distortion component is generated. Therefore, highly reliable communication can be performed without causing the communication device to malfunction.
The downstream transmission signal distributed by the distributor 10 is branched by the branching unit 11, the specified channel is selected from the television broadcast signal by the set-top box 12 and demodulated, and then the image and the sound are output by the television receiver 13. I do.
The communication signal branched by the branching unit 11 and demodulated by the high-frequency modem 15 is sent to the personal computer 14 for processing.
On the other hand, an upstream transmission signal output from the set-top box 12 to the service line 8 and an upstream data signal based on a command from the personal computer 14 are converted into an upstream transmission signal by the high-frequency modem 15 and output to the service line 8. .
The upstream transmission signal output from the set-top box 12 and the high-frequency modem 15 is amplified to a predetermined level by the high-power amplifier 9 through the branching unit 11 and the distributor 10, and is dropped through the drop line 8, the security device 7, and the tap-off 6. The signal is transmitted to the main branch amplifier 5. The upstream transmission signal transmitted to the main branch amplifier 5 is amplified to a predetermined level by the main branch amplifier 5, the main distribution amplifier 4, and the main amplifier 3, and transmitted to each communication device provided in the head end 1 for processing.
[0010]
Next, effects of the present embodiment will be described.
FIG. 5 shows a measurement system diagram for confirming the effect of demagnetization.
Numeral 40 denotes a multi-channel signal generator, which generates pseudo TV signals at intervals of 6 MHz in a downstream transmission frequency band of 70 MHz to 770 MHz. Reference numeral 41 denotes a high output amplifier which amplifies the pseudo TV signal to a predetermined output level (110 dBμ in this embodiment) and supplies the same to an input terminal of a distributor 44a as a DUT 44 via a high-pass filter 42 having a cutoff frequency of 70 MHz. You. The output terminal of the distributor 44a is terminated by dummy resistors 44b and 44c. The pseudo-television signal of the high output level input to the input terminal of the distributor 44a generates a distortion component of a downstream signal due to the magnetizing condition of the distribution transformer and the matching transformer constituting the distributor 44a, and the input terminal of the distributor 44a. Output a distortion component.
Then, from among the distortion components output from the input terminal of the distributor 44a, the low-pass filter 43 having a cutoff frequency of 55 MHz for extracting the distortion components included in the transmission frequency band (10 MHz to 55 MHz) of the upstream signal. The signal is input to a preamplifier 45 (a flat amplifier having a gain of 30 dB in this embodiment), and the output signal of the amplifier 45 can be measured by a spectrum analyzer 46.
FIG. 4A shows a distortion component signal in the 7 MHz to 60 MHz band of the distributor 44a before demagnetizing the ferrite (more specifically, the distribution transformer and the matching transformer), and has a high level (maximum) in the entire upstream signal band. It can be seen that a distortion signal of 52 dBμ) is generated.
On the other hand, FIG. 4B shows the measurement data of the distributor 44a in which the ferrite (more specifically, the distribution transformer and the matching transformer) is demagnetized, and no distortion component is generated in the upstream signal frequency band (measurement detection). Limit).
[0011]
Next, a second embodiment of the present invention will be described with reference to FIG.
In the following description, the same components as those of the demagnetizing method / manufacturing method of the distribution circuit according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
FIG. 6 shows a distributor 50 in which the case and the lid are formed of a synthetic resin material. FIG. 6A is a perspective view without the lid, FIG. 6B is a side view with the lid mounted, 50a is a case, 50f is a lid, and each is a synthetic resin. Made of material. 50b is an input terminal, 50c and 50d are output terminals, which are fixed to the frame 50g. 50e indicates a printed wiring board.
The method of manufacturing the distributor 50 is as follows. First, the distribution transformer 20, the matching transformer 21, and the passage of low-frequency current and DC current necessary for forming a distribution circuit on the printed wiring board 50e are blocked, and the frequency correction for frequency correction is performed. A capacitor C (not shown) is mounted and electrically connected by soldering or the like as necessary.
Next, a frame 50g to which the input terminals 50b, the output terminals 50c, and 50d are attached is fixed to the printed wiring board 50e after the soldering operation by soldering or the like.
Then, the printed wiring board 50e to which the frame 50g is attached is mounted on the case 50a, and is screwed and fixed to the boss of the case 50a with the screw 50i.
After that, as in the first embodiment, the ferrite (more specifically, the distribution transformer and the matching transformer) is demagnetized, and the lid 50f is attached to complete the distributor.
[0012]
It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the gist of the present invention.
In the first embodiment and the second embodiment, the demagnetizing method and the manufacturing method of the distribution circuit have been described. However, similar effects can be obtained even with a branch circuit as shown in FIG. FIG. 7A is an explanatory view of assembling the branching device, and FIG. 7B is a circuit diagram of the branching device shown in FIG. 7A. Reference numeral 60 denotes a branching device, and reference numeral 61 denotes a branching transformer. Like the distribution transformer 20 and the matching transformer 21, a closed magnetic type ferrite core that can pass a signal in a transmission frequency band without attenuation is used. The wire is wound a predetermined number of times.
Since the manufacturing method and the method of demagnetizing the ferrite (specifically, the branch transformer 61) are the same as those of the first and second embodiments, detailed description will be omitted.
[0013]
Next, an example in which a branch / distribution circuit is incorporated in a high-frequency device will be described in detail. FIG. 8 is a block diagram of a high-output bidirectional amplifier 70 provided with an output level measuring terminal 70a. 70b is an input terminal, 70c is an output terminal, 71 is a high output amplifying unit, and 72 is a branching device for branching a part of the output signal level. The high-output bidirectional amplifier 70 is configured to be able to supply operating power from an output terminal, 73 is a power supply separation filter, and 74 is a power supply unit. The demagnetizing method of the branch circuit 72 is the same as that of the first embodiment, so that the detailed description is omitted.
FIG. 9 shows an example of a high-output bidirectional amplifier 80 with a built-in distributor having a plurality of output terminals. 80b is an input terminal, 80c and 80d are output terminals, 81 is a high output amplifying unit, 82 is a distributor, and 83 is a power supply unit, which is supplied from a power input terminal 80a. Note that the demagnetizing method of the distribution circuit 82 is the same as that of the first embodiment, as described above, and a detailed description thereof will be omitted.
[0014]
Next, in this embodiment, a hand-held rod-shaped demagnetizer has been described. However, as shown in FIG. 10, any shape and function may be used as long as the ferrite can be demagnetized. The demagnetizer 120 shown in FIG. 10A is a handy type and has a different shape.
Further, the degaussing machine 100 shown in FIG. 10B can be demagnetized unattended by incorporating it into a production line, so that productivity is improved. In addition, 110 is a belt conveyor.
The demagnetizer 130 shown in FIG. 10C is formed in a plate type. The degaussing machine 130 performs degaussing by mounting a DUT (device to be degaussed) such that the surface to be degaussed is at the bottom.
The demagnetizer 140 shown in FIG. 10D is formed in a ring shape. The degausser 140 degausses the part (ferrite) to be degaussed by approaching it near the center of the ring.
Further, in this embodiment, the degaussing method has been described by gradually moving the degausser away from the DUT (device to be degaussed). However, if the degaussing machine is configured to gradually weaken the magnetic field, It goes without saying that it is only necessary to keep the degaussing machine in the operating state for a predetermined time required for degaussing while the machine is kept close to the DUT.
[0015]
【The invention's effect】
As described above in detail, according to the first aspect of the present invention, in a high frequency branch / distribution circuit including a transformer formed by winding a conductive wire around a ferrite,
Since the ferrite is demagnetized after the soldering of the components of the high-frequency branching / distribution circuit and the mounting of the printed wiring board are completed, the transformer formed by winding a conductive wire around the ferrite with less distortion is provided. The provided high frequency branching / distribution circuit can be provided.
[0016]
According to the second aspect of the present invention, in a high-frequency device including the high-frequency branching / distributing circuit,
Since the ferrite is demagnetized after the soldering operation of the components of the high-frequency device and the mounting operation of the printed wiring board are completed, the high-frequency device having the high-frequency branching / distributing circuit and having less distortion is provided. A manufacturing method can be provided. Further, since no distortion component of the downlink transmission signal occurs in the uplink transmission band, the reliability of bidirectional data communication can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram of a CATV system according to the present invention.
FIG. 2 is an assembly explanatory diagram and a circuit diagram of a distributor.
FIG. 3 is an explanatory diagram showing a procedure of a demagnetizing method of a distributor (distribution circuit).
FIG. 4 is a diagram showing measurement data for explaining a demagnetizing effect.
FIG. 5 is a measurement system diagram for confirming the effect of demagnetization.
FIG. 6 is an explanatory view for assembling a distributor according to a second embodiment.
FIG. 7 is an assembly explanatory diagram and a circuit diagram of a branching device according to a different embodiment.
FIG. 8 is a block diagram of a high power amplifier with an output level measuring terminal according to another embodiment.
FIG. 9 is a block diagram of a high-output amplifier with a distributor according to another embodiment.
FIG. 10 is an explanatory diagram showing an example in which the shape and function of the demagnetizer are different.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Head end device, 2 ... Transmission line, 3 ... Trunk amplifier, 4 ... Trunk distribution amplifier, 5 ... Trunk branch amplifier, 6 ... Tap-off, 7 ... Protector, 8 ... Drop-in line, 9.70-80 ... High output both Amplifier, 10.50 distributor, 11.60 distributor, 12 set-top box, 13 TV receiver, 14 personal computer, 15 high-frequency modem, 20 distribution transformer, 21 matching transformer, 22 ... Current passing coil, 23 ... Ferrite core, 30/100/120/130/140 ... Demagnetizer, 31 ... Working part, 32 ... Power switch, 40 ... Multi-channel signal generator, 41 ... High power amplifier, 42 ... High pass filter, 43 low pass filter, 44 DUT, 45 preamplifier, 46 spectrum analyzer.

Claims (2)

In a high-frequency branching / distribution circuit equipped with a transformer formed by winding a conductor around a ferrite,
A demagnetizing method for the high-frequency branch / distribution circuit, comprising: deferring the ferrite after completing the soldering of the components of the high-frequency branch / distribution circuit and the mounting work of the printed wiring board. In a high-frequency device including the high-frequency branching / distribution circuit,
A method for manufacturing a high-frequency device, comprising demagnetizing the ferrite after completion of a work of soldering parts of the high-frequency device and a work of mounting a printed wiring board.

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