JPH05159192A - Signal transmission system - Google Patents

Abstract

PURPOSE:To provide the signal transmission system with superior signal transmission efficiency not as a noise source capable of preventing the entry of the external noise between a rotation part and a stationary part. CONSTITUTION:An antenna unit 46 consists of a stationary part 110 and a rotation part 111. The rotation part 111 is provided with a hollow cylindrical part and a disk part 111b. The stationary part 110 is provided with three concentric circle grooves 110A and 110B. In the groove 110A, antennas 121 and 131 are formed on printed circuit boards 120 and 130, and a sliding joint part formed by carbon tool steels or the like is provided. A channel with good transfer efficiency and not causing the mutual interference can be selected by using the antenna unit 46, transmitting plural channels simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device, and more particularly to improvement of a signal transmission system between a rotary antenna and a fixed antenna.

[0002]

2. Description of the Related Art Conventionally, a wired method such as a slip ring is used for signal transmission between a rotating portion and a fixed portion. However, this method is not suitable for transmitting a high frequency signal such as an image due to the inclusion of noise. On the other hand, a wireless system using a transmitting antenna and a receiving antenna is being used. However, in this system, it is inevitable that external noise is mixed into the receiving system and the transmitting system itself becomes a noise source, and accurate signal transmission is not possible. There was a problem if requested. Therefore, the applicant of the present application previously filed Japanese Patent Application No. 02-3
No. 27176 and Japanese Patent Application No. 03-067214 propose a signal transmission device in which a transmitting antenna and a receiving antenna are arranged to face each other in a hollow electromagnetic shield, and one of the antennas is fixed and the other is rotated.

12 and 13 show the principle of this signal transmission device. In the case of the signal transmission device shown in FIG.
A pair of two ring-shaped conductors 101 and 102, each of which has a lead wire drawn out, are coaxially opposed to each other in the hollow electromagnetic shield body 103 at predetermined intervals, and one of the ring-shaped conductors is arranged. With reference to the axis A
It is configured to be rotatable in the circumferential direction indicated by. In addition, FIG.
In the case of 3, the three sets of ring-shaped conductors 201, 20 each of which has a lead wire drawn in the hollow electromagnetic shield body 203
2, 204, 205, 206, and 207 are coaxially opposed to each other at a predetermined interval, and one of the ring-shaped conductors is rotatable in the circumferential direction indicated by a symbol A ₁ about the axis. is doing.

[0004]

However, in the above signal transmission device, although it is possible to prevent mixing of external noise and prevent the transmission system itself from becoming a noise source, the rotation of the symbols A and A ₁ is prevented. There is a problem in that the positional relationship between the conductor portions existing between the ring-shaped conductors 200 is subtly changed depending on the position to cause cavity resonance, and there are cases where signal transmission can be performed reliably and cases where it is not possible. there were.

Therefore, an object of the present invention is to prevent a noise from being mixed in from outside in the signal transmission system between the rotating part and the fixed part, and to prevent the transmitting system itself from becoming a noise source, and to change the rotating position. An object of the present invention is to provide a signal transmission method capable of reducing cavity resonance and performing reliable signal transmission.

[0006]

In order to solve the above-mentioned problems, the present invention provides a ring-shaped hollow chamber provided in an electromagnetic shield body in which a transmission side and a reception side, from which a conductor is drawn, are paired in a ring shape. The conductors are coaxially arranged facing each other at a predetermined interval,
A signal transmission method applied to a signal transmission device in which one of the ring-shaped conductors is rotatably provided in a circumferential direction around the shaft, wherein the transmission efficiency in the signal transmission device is good, and , Multiple frequency bands that do not interfere with each other are selected and signal transmission is performed simultaneously.

As the frequency band, the UHF band is selected.

[0008]

According to the present invention, since the ring-shaped conductors on the transmitting side and the receiving side are provided in the electromagnetic shield, there is no external influence, and the transmitting system itself becomes a noise source. Never. On the other hand, since the ring-shaped conductor is arranged in the groove (cavity), the transmission efficiency is extremely deteriorated due to the cavity resonance depending on the carrier wave to be transmitted, but the transmission efficiency is good and A carrier having a frequency that does not cause interference is selected and a plurality of carriers are simultaneously transmitted.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. 1 (A), (B), (C) and FIG.
In addition, the antenna unit 46 which is the signal transmission device of the present invention.
3A shows a top view of the antenna unit 46, and FIG. 3B shows a bottom view of the antenna unit 46.

As shown in FIGS. 1 (A), (B), (C) and FIG. 2, the antenna unit 46 includes a fixed portion 1 made of an electromagnetic shield member (eg, aluminum).
10 and the rotating unit 111 and the like.

The rotating part 111 is a disk-shaped circular disk part 11
A cylindrical portion 111a is formed downward at the center of 1b. A printed circuit board 120 constituting a transmitting antenna AT is fixed to a predetermined position on the lower surface of the disk portion 111b described later, and the antenna 1 is mounted on the lower surface of the printed circuit board 120.
21 is fixed. The printed circuit board 120 is made of glass epoxy resin, and as shown in FIGS.
A copper coating is attached to both surfaces of the antenna 121, and a thin strip-shaped antenna 121 is formed by etching, and a ground 122 covered with the copper coating is formed on the entire surface.

A printed circuit board 130 constituting a receiving antenna RX is arranged facing the printed circuit board 120, and the printed circuit board 130 is also provided with an antenna 131, a ground 132 and the like as described above. here,
In order to obtain impedance matching between the transmitting side and the receiving side of the antenna, the thickness of each of the printed boards 120 and 130 is 1.6 mm, the width of each of the antennas 121 and 131 is 2.75 mm, and the transmitting antenna AT and the receiving antenna RX are the same. Is 1 mm, and the gap between the grounds 122 and 132 and the lead wires 81 and 82 is 1.6 mm. The lead wires 81 and 82 each have a function of connecting a signal to the outside.

By setting the numerical values in this way, both the impedances of the transmitting side antenna AT and the receiving side antenna RX become 50Ω, impedance matching can be performed, and a standing wave (SWR) is not generated, It is possible to send and receive signals without noise.

On the lower surface of the antenna 121, a Teflon TF having a thickness of 0.2 mm is attached to prevent contact with the opposing antenna 131 as described later (see FIG. 2).

In the fixing portion 110, three concentric circular grooves 110A, 110B having a rectangular cross section,
110C is formed. The depth of the groove 110A is 15 m
m and the width is 10 mm. As shown in FIG. 2, the printed circuit boards 120 and 130 are fixed in the groove 110A, and antennas 121 and 131 are attached to the facing surfaces of the printed circuit boards 120 and 130, respectively. Printed circuit boards 120, 130, antennas 121, 131, etc. are similarly attached to the grooves 110B, 110C, respectively.

Then, the disk portion 111 of the rotating portion 111.
Disc-shaped sliding contact portion 1 made of carbon tool steel or the like on the lower surface of b
14 is attached (see FIG. 2), and the fixed portion 11
With the conductive resin: conductive nylon material {for example, conductive MC nylon (Nippon Polypenco Co., Ltd.)} attached to the sliding contact surface other than the groove of 0, the fixed portion 110 and the rotating portion 111 are overlapped. One antenna 46 is formed.

11 formed on the fixing portion 110 in this way
In the three grooves 0A, 110B, and 110C, a carrier wave c corresponding to image information (inner bottom surface information and inner surface information of the laminate tube) is transmitted from the rotating portion to the fixed portion in the groove 110B as described later with reference to FIG. The grooves 110A and 110C are used as antennas for the first and second horizontal and vertical synchronization signals s from the quality determination device 65, respectively.
_The carrier waves d and e corresponding to ₁ and s ₂ are used as antennas for transmitting to the CCD camera of each in-tube inspection device 55. Since the antennas in the groove are electromagnetically shielded from each other, they do not give noise to each other.

Next, an outline of a rotary tube inspection machine to which the signal transmission device according to the present invention is applied will be described. As shown in FIG. 7, the rotary tube inspection machine 50
A fixed shaft (not shown) is erected on the base 51, and a coaxial rotating shaft 52 is attached so as to cover the fixed shaft. A rotation inspection base 53 and a member mounting base 54 are fixed to the rotary shaft 52, and these bases rotate at a predetermined speed together with the rotary shaft 52.

The antenna portion 46 is attached to the upper end of the rotary shaft 52, the rotary portion 111 (see FIG. 1) of the antenna portion is attached to the rotary shaft 52, and the fixed portion 110 is attached to the fixed shaft (not shown). ..

The laminate tube T, which is the object to be inspected, is conveyed by the conveying device and is sequentially inserted into the holder elevating and rotating shaft 56 provided on the rotation inspection table 53. The holder raising / lowering rotation shaft 56 is configured to be vertically moved by a cam while rotating on its own axis. An in-tube inspection device 55 is attached to the lower surface of the member mounting base 54, and the in-tube insertion portion 57 inserted into the laminated tube T inspects the inner surface of the laminated tube T.

As shown in FIG. 8, the operation of the rotary tube inspecting machine 50 constructed in this way is as shown in FIG. 8, in which the rotating inspection table 53 revolves in the direction of rotation while rotating at the inspection position. At points P ₁ , P ₂ , P ₃ , and P ₄ , rotation is temporarily stopped for a predetermined time. In this state, the tube insertion portion 57 of the in-tube inspection device 55 is inserted into the laminated tube T, and the laminated tube T is moved to the point P ₁
By intermittently performing rotation between P ₄ and
The in-tube inspection device 55 inspects the tube inner bottom surface and the tube inner side surface in each section. At each point, the inner surface of the laminate tube T is divided into four parts and inspected, as indicated by the double diagonal lines.

The processing of the inspection information is processed by the processing system shown in FIG. 9, and the quality of the laminated tube is judged. The processing system includes a rotating block and a fixed block.

That is, as shown in FIG. 9, among the inspection information obtained by the in-tube inspection device 55, “inside” from four tube insertion parts (heads) 57 (for example, first to fourth heads). The “bottom surface information” is sent to the RF converter 61 as a video signal. On the other hand, the “inside surface information” from the four tube insertion portions (heads) 57 (for example, the first to fourth heads) is sent to the RF converter 61 as an audio signal, and the RF converter 61 outputs the “inside surface information” together with the video signal. R
It is converted into an F signal and sent to the mixer 62 as an RF signal a. The RF signal a is modulated into a carrier wave c having a predetermined frequency in the mixer 62 and sent to the groove 110B (see FIG. 1C) of the rotating portion of the antenna unit 46.

Then, the carrier wave c is received by the fixed part of the antenna section 46, and is sent to the tuner 64 as a signal distributed by the distributor 63 to the four heads. The transmitted signal is divided by the tuner 64 into a video signal for four heads and an audio signal for four heads based on four predetermined tuning points. These signals are sent to the quality determination device 65, where the quality of the inner surface state of each laminate tube is determined by a method such as image binarization processing.

On the other hand, from the pass / fail judgment device 65, the first horizontal / vertical synchronizing signal s ₁ is sent to the mixer 66a for synchronizing the CCD camera (not shown), and the second horizontal / vertical synchronizing signal S is sent. ₂ is sent to the mixer 66b. Each mixer 66
The grooves 110A and 110C of the fixed portion of the antenna unit 46 are modulated by the predetermined carrier waves d and e at a and 66b, respectively.
(See FIG. 1). Then, the carrier waves d and e are received by the rotating part of the antenna part 46, and are respectively distributed by the distributor 6
Signals corresponding to the first horizontal vertical synchronizing signal and the second horizontal vertical synchronizing signal are distributed by 7a and 67b and sent to the CCD camera of the in-tube inspection device 55.

Next, a case will be described in which UHF waves of a plurality of channels are simultaneously transmitted and received using the antenna section 46 configured as described above. By the way, the antenna 46 having the configuration shown in FIGS. 1 to 6 causes a cavity resonance due to a cavity formed by a groove (see FIG. 1C). Therefore, for example, as shown in FIG. 11, the transmission efficiency of the antenna greatly changes depending on the frequency band. That is, if a frequency band with poor transmission efficiency is selected, sufficient signal transmission cannot be performed.

Therefore, in the case of the transmission efficiency characteristics shown in FIG. 11, among the UHF television broadcasting channels in Japan shown in Table 1, the first head corresponds to 14ch, the second head to 16ch, and the third head. 25ch and the 4th head to 29ch respectively.
Transmission is divided into two groups of 4ch and 16ch and 25ch and 29ch. Here, each channel selects a frequency that does not cause mutual interference.

[0028]

[Table 1] Then, as shown in FIG. 10, when the first head reaches the position P ₄ , signals of four channels shown in the figure are simultaneously transmitted from the first to fourth heads as the first transmission. By doing so, for example, as shown in Table 2, signal transmission can be efficiently performed. When another frequency is selected, there is an attenuation of -80 to -90 dBm, and reliable signal transmission cannot be performed.

[0029]

[Table 2] When the second head reaches the position P ₄ , the second head
The signals of the illustrated channels are simultaneously transmitted from the second to fifth heads as the number of times of transmission.

Further, when the third head reaches the position P ₄ , the signals of the channels shown in the figure are simultaneously transmitted from the third to sixth heads as the third transmission. In this embodiment, the optimum channel for the signal transmission characteristic shown in FIG. 11 is selected. However, in the case of a signal transmission device having another signal transmission characteristic, the signal transmission characteristic of the signal transmission device is checked and Just select the best channel. That is, it suffices to select a channel according to the cavity resonance characteristic of each signal transmission device and transmit the signal.

[0031]

As described above, according to the present invention,
Signal transmission can be performed in a non-contact manner between the rotating portion and the fixed portion, and a channel corresponding to a portion having high transmission efficiency is selected, so that signal transmission can be reliably performed.

[Brief description of drawings]

FIG. 1 shows components of an antenna according to an embodiment of the present invention,
(A) is a rotating part, (B) is a fixed part, (C) is a figure which shows the case where a rotating part and a fixed part are combined, respectively.

FIG. 2 is an enlarged view of a main part of the antenna.

3A is a top view of the antenna, and FIG. 3B is a bottom view.

4A is a cross-sectional view of the antenna, and FIG. 4B is a diagram showing impedance matching between a transmitting side and a receiving side.

FIG. 5 is a dimensional diagram of a main part of the antenna.

FIG. 6 is a perspective view of the antenna.

FIG. 7 is a schematic perspective view of a rotary tube inspection device to which the present invention is applied.

FIG. 8 is a schematic view of the operation of the rotary tube inspection device.

FIG. 9 is a schematic block diagram of an inspection information processing system of the rotary tube inspection device.

FIG. 10 is a conceptual diagram showing that four types of inspection information of the rotary tube inspection device are simultaneously transmitted.

FIG. 11 is a conceptual diagram when an optimum channel is selected and transmitted according to transmission efficiency.

FIG. 12 is a principle diagram when a pair of antennas of a conventional signal transmission device is used.

FIG. 13 is a principle diagram of a conventional signal transmission device having three pairs of antennas.

[Explanation of symbols]

 46 ... Antenna unit 110 ... Fixed part 110A, 110B, 110C ... Groove 111 ... Rotating part 111a ... Cylindrical part 111b ... Disc part 121, 131 ... Antenna TF ... Teflon

Claims (2)

[Claims] 1. A ring-shaped hollow chamber provided in an electromagnetic shield body is provided with a pair of ring-shaped conductors having a pair of a transmission side and a reception side from which a conductor is drawn, and which are coaxially opposed to each other at a predetermined interval. A signal transmission method applied to a signal transmission device in which one of the ring-shaped conductors is rotatably provided in a circumferential direction around the shaft, wherein the transmission efficiency in the signal transmission device is good, and , A signal transmission method characterized in that a plurality of frequency bands that do not interfere with each other are selected and signal transmission is performed simultaneously. 2. The signal transmission system according to claim 1, wherein the frequency band is a UHF band.