JP4289840B2 - Demagnetizing method of high frequency branching / distribution circuit and manufacturing method of high frequency device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ferrite demagnetization method in a high-frequency branch / distribution circuit having a transformer formed by winding a winding around a ferrite, and a method of manufacturing a high-frequency device having the high-frequency branch / distribution circuit .
[0002]
[Prior art]
In recent years, CATV systems have not only transmitted VHF / UHF band signals and uplink signals, but also widened bands (for example, compatible with 10 to 2150 MHz) including intermediate frequencies of BS broadcasts and 110 ° CS broadcasts. On the other hand, in high-frequency branching / distribution circuits equipped with a transformer in which conducting wires are wound around ferrite, ferrite has been downsized and magnetic materials have been improved in order to cope with this wide band.
However, when the conventional high frequency branch / distribution circuit is connected to a bidirectional CATV amplifier due to the increase in the number of channels and the increase in the output of the amplifier due to the wide bandwidth, the transformer provided in the high frequency branch / distribution circuit can be used. A distortion component is generated in the formed ferrite, and a distortion component in the upstream transmission frequency band among the distortion components becomes an upstream inflow noise and interferes with the CATV center apparatus.
[0003]
Since this problem occurs because the ferrite is slightly magnetized, as a countermeasure, the ferrite is demagnetized by heat treatment at a temperature slightly higher than the Curie temperature inherent to the ferrite, and then the ferrite. A transformer is formed by winding a conductive wire on the wire, and a method of assembling a high-frequency branch / distribution circuit using the transformer, or a transformer unit in which a conductive wire is wound around ferrite is assembled, and then the transformer is used with a demagnetizer. A method of assembling the high-frequency branch / distribution circuit after demagnetizing was considered.
[0004]
[Problems to be solved by the invention]
However, with the conventional demagnetization method by heat treatment of ferrite, handling of the ferrite after heat treatment, tools used for winding a conductor (such as tweezers), or soldering for electrically connecting each component The ferrite may become magnetized again during the work, or when the assembled printed wiring board is fixed to the case with screws, and it takes time for the heat treatment in process control. , There was a problem that the unit price of parts was also high.
Also, in the method of assembling the transformer itself after degaussing with a demagnetizer, the ferrite is magnetized by the tools (for example, tweezers, soldering iron, screwdriver, etc.) used in the assembly of the transformer. There is the same problem as the method, and the current situation is that it is very difficult to manage the process for stable assembly.
The present invention has been made in view of these problems, and an object of the present invention is to prevent distortion components from being generated in a high-frequency signal in a high-frequency branch / distribution circuit having a transformer formed by winding a conducting wire around a ferrite. It is an object of the present invention to provide a demagnetization method for a high-frequency branch / distribution circuit that can demagnetize ferrite .
Another object is to demagnetize the ferrite so that no distortion component is generated in the high-frequency signal in a high-frequency device having a high-frequency branch / distribution circuit having a transformer formed by winding a conductive wire around the ferrite. It is to provide a method for manufacturing a high-frequency device.
[0005]
[Means for Solving the Problems]
The invention according to claim 1 made to achieve the above object is a method for demagnetizing the ferrite in a high-frequency branching / distributing circuit including a transformer formed by winding a conducting wire around the ferrite,
Soldering to the printed circuit board components of the high-frequency branch and distribution circuit including the transformer, and, after the mounting operation completion to the case of the printed wiring board, and performing demagnetization of the ferrite .
[0006]
The invention according to claim 2 is a method of manufacturing a high-frequency device having a high-frequency branching / distribution circuit having a transformer formed by winding a conducting wire around a ferrite,
Soldering to the printed circuit board components of the high frequency apparatus including the high-frequency branch and distribution circuit, and, after the mounting operation completion to the printed wiring board of the case, constituting the high-frequency branch and distribution circuits The ferrite is demagnetized .
[0007]
DETAILED DESCRIPTION OF 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, where 1 is a headend device, 2 is a transmission line, 3 is a trunk amplifier, 4 is a trunk distribution amplifier, and 5 is a trunk branch. Amplifier, 6 tap-off, 7 protector, 8 lead-in wire, 9 high-power bidirectional amplifier, 10 distributor, 11 branching device, 12 set-top box, 13 TV receiver, 14 personal computer, Reference numeral 15 denotes a high frequency modem.
[0008]
Next, the manufacturing method of the divider | distributor 10 which employ | adopted this invention is demonstrated in detail using FIGS.
FIG. 2 (A) is an assembly explanatory diagram of the distributor, and FIG. 2 (B) is a circuit diagram of the distributor shown in FIG. 2 (A).
Reference numeral 10a denotes a case, which is formed of a metal material having good conductivity, such as zinc die casting or aluminum die casting. An input terminal 10b and output terminals 10c and 10d are integrally formed in the case 10a. Reference numeral 10e denotes a printed wiring board on which a distribution circuit is formed, and reference numeral 10f denotes a lid body made 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 the output terminal 10c or 10d at one end to the input terminal 10b, which are necessary for constituting a distribution circuit on the printed wiring board 10e, and , A capacitor C not described for preventing the passage of a low-frequency current or a direct current or correcting the 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 the transmission frequency band can pass without being attenuated, and an insulated wire is wound around the ferrite core 23 a required number of times. . As the ferrite core 23, for example, DL · QM · KP series manufactured by Hitachi Ferrite Co., Ltd. is used. As the ferrite used in the present invention, for example, a ferrite belonging to the Ni—Zn system or Ni—Cu—Zn system and having a small loss (tan σ / μi) at a high frequency is employed. 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 terminal 10b and the output terminals 10c and 10d are electrically connected by soldering or the like.
Thereafter, before the lid 10f is mounted, 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 operating part 31 of the demagnetizer 30 is brought close to the position close to the ferrite core, the operation power switch 32 of the demagnetizer 30 is set to the operating state, and then the demagnetizer 30 is operated. The working part 31 of the demagnetizer 30 is gradually moved away from the ferrite core while being left to a predetermined distance (for example, 30 cm) where the demagnetizer 30 does not act, and then the operation power switch 32 of the demagnetizer 30 is turned off. , Non-operating state. This completes the demagnetization of the ferrite.
When the demagnetization of the ferrite is completed, the lid 10f is attached to 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 not described, a satellite broadcast receiver, and various communication devices (communication control device, transmission device, various servers, etc.) 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 converted into downlink transmission signals (for example, 70 MHz to 770 MHz) that do not overlap in frequency, and are downstream via the transmission line 2. Is output. The downstream transmission signal is amplified to a predetermined level by each main line amplifier 3, main line distribution amplifier 4, and main line branching amplifier 5, and is drawn into the building facility via the tap-off 6, the protector 7, and the lead-in line 8.
The downstream transmission signal drawn into the building facility is amplified to a predetermined level by the high output 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 is possible without causing the communication device to malfunction.
The downlink transmission signal distributed by the distributor 10 is branched by the branching unit 11, and after the designated channel is selected and demodulated by the set top box 12, the image / sound is output by the television receiver 13. To 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, the upstream transmission signal output from the set top box 12 to the service line 8 side and the upstream data signal based on the command instructed from the personal computer 14 are converted into the upstream transmission signal by the high frequency modem 15 and output to the service line 8 side. .
The upstream transmission signals output from the set top box 12 and the high frequency modem 15 are amplified to a predetermined level by the high output amplifier 9 via the branching unit 11 and the distributor 10, and are passed through the lead-in line 8, the protector 7, and the tap-off 6. It is transmitted to the main branching amplifier 5. The upstream transmission signal transmitted to the main line branch amplifier 5 is amplified to a predetermined level by the main line branch amplifier 5, the main line distribution amplifier 4, and the main line amplifier 3, and is transmitted to each communication device provided in the head end 1 for processing.
[0010]
Next, the effect of the present embodiment will be described.
FIG. 5 shows a measurement system diagram for confirming the effect of demagnetization.
Reference numeral 40 denotes a multi-channel signal generator, which generates a pseudo TV signal at intervals of 6 MHz in a downstream transmission frequency band of 70 MHz to 770 MHz. Reference numeral 41 denotes a high-power amplifier that amplifies the pseudo TV signal to a predetermined output level (110 dBμ in this embodiment), and is supplied to an input terminal of a distributor 44a as a DUT 44 through a high-pass filter 42 having a cutoff frequency of 70 MHz. The The output terminal of the distributor 44a is terminated with dummy resistors 44b and 44c. A high output level pseudo television signal input to the input terminal of the distributor 44a generates a distortion component of the downstream signal due to the magnetic state of the distribution transformer and the matching transformer constituting the distributor 44a, and the input terminal of the distributor 44a. Produces a distortion component.
Then, through a low-pass filter 43 having a cutoff frequency of 55 MHz for extracting a distortion component included in the transmission frequency band (10 MHz to 55 MHz) of the upstream signal among the distortion components output from the input terminal of the distributor 44a, A preamplifier 45 (a flat amplifier having a gain of 30 dB in this embodiment) is input, and an output signal of the amplifier 45 can be measured by a spectrum analyzer 46.
FIG. 4A shows a distortion component signal in the band from 7 MHz to 60 MHz of the distributor 44a before demagnetizing the ferrite (specifically, the distribution transformer and the matching transformer). It can be seen that a distortion signal of 52 dBμ is generated.
On the other hand, FIG. 4B shows measurement data of the distributor 44a in which the ferrite (specifically, the distribution transformer and the matching transformer) is demagnetized, and no distortion component is generated in the upstream signal frequency band (measurement detection). You can see that
[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 in the demagnetizing method / manufacturing method of the distribution circuit of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 6 shows a distributor 50 in which the case and the lid are made of a synthetic resin material. 6A is a perspective view of a state where the lid is removed, FIG. 6B is a side view of the state where the lid is mounted, 50a is a case, and 50f is a lid, each of which is a synthetic resin. Made of material. 50b is an input terminal, and 50c and 50d are output terminals, which are fixed to the frame 50g. Reference numeral 50e denotes a printed wiring board.
In the manufacturing method of the distributor 50, first, the distribution transformer 20, the matching transformer 21 and the low-frequency current and the direct current that are necessary for constructing the distribution circuit on the printed wiring board 50e are blocked, or the frequency correction is performed. Mount a capacitor C (not shown), and connect it electrically by soldering if necessary.
Next, the frame 50g to which the input terminals 50b and 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 into the boss of the case 50a with a screw 50i to be fixed.
Thereafter, similarly to the first embodiment, the demagnetization of the ferrite (specifically, the distribution transformer and the matching transformer) is performed, and when the lid 50f is attached, the distributor is completed.
[0012]
It should be noted that the present invention is not limited to the above embodiment, and can be implemented with appropriate modifications without departing from the spirit 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, the same effect can be obtained even in a branch circuit as shown in FIG. FIG. 7A is an explanatory diagram of assembly of the branching device, and FIG. 7B is a circuit diagram of the branching device shown in FIG. 60 is a branching device, and 61 is a branching transformer. Like the distribution transformer 20 and the matching transformer 21, a closed-magnet type ferrite core that allows a signal in the transmission frequency band to pass through without attenuation is used. The electric wire is wound a predetermined number of times.
Note that the manufacturing method and the demagnetizing method of the ferrite (specifically, the branch transformer 61) are the same as those in the first and second embodiments, and thus detailed description thereof is 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-power bidirectional amplifier 70 provided with an output level measurement terminal 70a. 70b is an input terminal, 70c is an output terminal, 71 is a high output amplifier, and 72 is a branching device that branches a part of the output signal level. The high-power bidirectional amplifier 70 is configured to be able to supply operating power from the output terminal, 73 is a power supply separation filter, and 74 is a power supply unit. Since the demagnetization method of the branch circuit 72 is the same as that of the first embodiment, a detailed description thereof will be omitted.
FIG. 9 shows an example of a high-power bidirectional amplifier 80 with a built-in distributor having a plurality of output terminals. Reference numeral 80b is an input terminal, 80c and 80d are output terminals, 81 is a high-power amplifier, 82 is a distributor, and 83 is a power supply supplied from the power input terminal 80a. Since the demagnetizing method of the distribution circuit 82 is the same as that of the first embodiment, the detailed description is omitted.
[0014]
Next, in this embodiment, the hand-held rod-shaped demagnetizer has been described. However, any shape and function may be used as long as the ferrite can be demagnetized as shown in FIG. The demagnetizer 120 shown in FIG. 10A is a handy type and has a different shape.
Further, since the demagnetizer 100 shown in FIG. 10B can be degaussed unattended by being incorporated in a production line, productivity is improved. Reference numeral 110 denotes a belt conveyor.
Further, the demagnetizer 130 shown in FIG. 10C is formed in a plate shape. The demagnetizer 130 is demagnetized by placing a DUT (device to be degaussed) so that the surface to be demagnetized becomes the bottom.
Further, the demagnetizer 140 shown in FIG. 10D is formed in a ring shape. The demagnetizer 140 demagnetizes the part (ferrite) to be demagnetized close to the center of the ring.
Furthermore, in this embodiment, the demagnetization method has been described by gradually moving the demagnetizer away from the DUT (device to be demagnetized). However, when the magnetic field generated by the demagnetizer is gradually weakened, It goes without saying that it is only necessary to keep the demagnetizer in an operating state for a predetermined time required for demagnetization while keeping the machine close to the DUT.
[0015]
【The invention's effect】
As described in detail above , according to the demagnetizing method of the high-frequency branch / distribution circuit according to claim 1 , the operation of soldering the components of the high-frequency branch / distribution circuit including the transformer to the printed wiring board , and Since the ferrite constituting the transformer is demagnetized after completion of the operation of attaching the printed wiring board to the case, it is possible to provide a high-frequency branch / distribution circuit with less generation of distortion components of the high-frequency signal .
[0016]
According to the method for manufacturing a high-frequency device according to claim 2, soldering of the components of the high-frequency device including the high-frequency branch / distribution circuit to the printed wiring board , and the case of the printed wiring board Since the ferrite constituting the high-frequency branch / distribution circuit is demagnetized after the mounting operation is completed, a high- frequency device with less generation of distortion components of the high-frequency signal can be provided.
[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 view and a circuit diagram of a distributor.
FIG. 3 is an explanatory diagram showing a procedure of a demagnetization 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 assembly explanatory diagram of 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 measurement terminal according to a different embodiment.
FIG. 9 is a block diagram of a high-power amplifier with a distributor according to a different embodiment.
FIG. 10 is an explanatory view showing an example in which the shape and function of the demagnetizer are different.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Head end apparatus, 2 ... Transmission line, 3 ... Trunk amplifier, 4 ... Trunk distribution amplifier, 5 ... Trunk branch amplifier, 6 ... Tap off, 7 ... Guard, 8 ... Lead-in line, 9/70/80 / High output both Directional amplifier, 10.50 ... distributor, 11.60 ... branch, 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)

A method for demagnetizing the ferrite in a high-frequency branch / distribution circuit having a transformer formed by winding a conducting wire around the ferrite ,
Soldering to the printed circuit board components of the high-frequency branch and distribution circuit including the transformer, and, after the mounting operation completion to the case of the printed wiring board, and performing demagnetization of the ferrite Demagnetization method for high frequency branch / distribution circuit. A method of manufacturing a high-frequency device having a high-frequency branch / distribution circuit having a transformer formed by winding a conductive wire around a ferrite,
Soldering to the printed circuit board components of the high frequency apparatus including the high-frequency branch and distribution circuit, and, after the mounting operation completion to the printed wiring board of the case, constituting the high-frequency branch and distribution circuits A method for manufacturing a high-frequency device, wherein the ferrite is demagnetized.

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