JP2004111805A - Interface circuit unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit noises leaked to an analogue cable in the case where the analogue cable and a digital cable are arranged, being overlapped with each other in a planar manner. <P>SOLUTION: A unit is provided with; a first circuit board 3 having an analogue output 11; a second circuit board 4 having an analogue input 12 and a digital output 14; a metal fixing plate 2 for fixing the first and the second circuit boards 3, 4, being distanced from each other; an analogue cable 13 for connecting the analogue output 11 and the analogue input 12 passing through a spacing region 5 between the circuit boards 3, 4; and a digital cable 15 which is connected to the digital output 14, being overlapped with the analogue cable 13 in a planar manner. The unit is further provided with an opening 16 in the spacing region 5 so as to allow communication between the front and the rear of the fixing plate 2. The digital cable 15 is led out to the rear of the fixing plate 2 through the opening 16. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an interface circuit unit including a circuit that converts an analog signal into a digital signal and outputs the digital signal, and more particularly to an interface circuit unit that prevents noise output from a digital cable from leaking to an analog cable. .
[0002]
[Prior art]
When a circuit that converts an analog signal into a digital signal and outputs the digital signal is provided on a single circuit board, an analog circuit unit as described in Patent Literature 1 is used to prevent noise due to the digital signal from leaking into the analog signal. And a digital circuit part are separated by using a shield plate.
[0003]
[Patent Document 1]
Published Japanese Utility Model Application No. 5-90997
[Problems to be solved by the invention]
When the cable connected to the circuit board is only analog, as in Patent Document 1, the digital circuit portion can be surrounded by a shield plate. However, when a digital cable is connected to the circuit board, noise generated from this cable is used. Is a problem. In particular, when it is necessary to arrange the analog cable and the digital cable so as to overlap with each other due to a problem in the configuration of the circuit board, there is a problem that noise generated from the digital cable easily leaks to the analog cable.
[0005]
Therefore, an object of the present invention is to provide a structure capable of suppressing noise leaking to an analog cable when an analog cable and a digital cable are arranged so as to overlap in a plane.
[0006]
[Means for Solving the Problems]
According to the present invention, a first circuit board having an analog output section, a second circuit board having an analog input section and a digital output section, and the first and second circuit boards are provided. A metal mounting board that fixes the analog output section and the analog input section through a space area of the circuit board, and an analog cable that is connected to the digital output section. A digital cable arranged with a planar overlap, provided in the space area of the mounting board, an opening communicating the front and back of the mounting board, and the digital cable was led out to the back side of the mounting board from this opening. It is characterized by the following.
[0007]
According to a second aspect of the present invention, the opening is formed in a region that avoids a planar overlap with the analog cable.
[0008]
According to a third aspect of the present invention, a tunnel-like passage portion for arranging the digital cable is formed adjacent to the opening of the mounting board.
[0009]
According to a fourth aspect of the present invention, the analog output section of the first circuit board and the analog input section of the second circuit board face each other with the tunnel-shaped passage section interposed therebetween. First, the second circuit board is fixed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a state in which a top cover of an interface circuit unit is removed, and FIG. 2 is a perspective view of a mounting board.
[0011]
In the interface circuit unit 1, the first circuit board 3 and the second circuit board 4 are fixed to one surface of the mounting board 2 with a space region 5 therebetween so that there is no planar overlap. . Various signal terminal units 6 and 7, such as an analog signal input / output, a video signal input, a composite video output, and an RS232C signal input / output, and a power supply terminal 8 are arranged on the lower and right sides of the unit 1. The unit 1 includes a lower plate 9 on which various signal terminal portions 6 and power supply terminals 8 are arranged on a lower portion thereof, and the lower plate 9 is fixed to the mounting board 2 with screws. The right side plate of the unit 1 on which the various signal terminal portions 7 are arranged is formed by bending the mounting board 2.
[0012]
A metal cover 10 (see FIG. 3) is attached so as to cover the first and second circuit boards 3 and 4. The metal cover 10 and the mounting substrate 2 also function as a shield plate by being connected to the ground potential.
[0013]
The first circuit board 3 is a circuit exclusively handling analog signals, and is fixed to the mounting board 2 so as to occupy one side of the unit 1 in the left-right direction. The second circuit board 4 is a circuit that handles both an analog signal and a digital signal in order to perform digitization processing for digitizing an analog signal or perform scaling processing for changing the size of an image. Is fixed to the mounting board 2 in a region other than the region occupied by the first circuit board 3.
[0014]
The first circuit board 3 includes a connector 11 as an analog output unit that outputs an analog signal supplied via the terminal 7. The second circuit board 4 includes a connector 12 as an analog input unit to which an analog signal supplied from the first circuit board 3 is input. These connectors 11 and 12 are opposed to each other with the space region 5 interposed therebetween so as to be connected to each other by an analog cable 13 passing over the space region 5.
[0015]
The second circuit board 4 has a connector 14 as a digital output unit disposed on the same side edge as the side edge on which the connector 12 for analog output is provided. One end of a digital cable 15 is connected to the connector 14. The digital cable 15 is constituted by a cable suitable for a digital interface. In this example, a plurality of twisted pairs for transmitting a parallel-to-serial converted data signal, clock signal, or the like with reduced amplitude are used. Then, the digital cable 15 is pulled out from the lower portion of the unit so that the other end is connected to a digital device, for example, a digital input liquid crystal display device.
[0016]
At this time, since the digital cable 15 passes under the analog cable 13, the digital cable 15 and the analog cable 13 are arranged with a planar overlap. In order to prevent noise from leaking from the digital cable 15 to the analog cable 13 arranged with a planar overlap, a shielding member is arranged between the two. As the member for shielding, a part of the mounting substrate 2 was used. An opening 16 that connects the front and back of the mounting substrate 2 is provided at a position corresponding to the interval region 5 of the mounting substrate 2. The opening 16 is formed in a region that avoids a planar overlap with the analog cable 13. Here, the opening 16 is formed at a position adjacent to the connector 14 for digital output.
[0017]
The digital cable 15 is pulled out to the back side of the unit 1 through the opening 16 and the metal mounting board 2 is interposed at the intersection of the analog cable 13 and the digital cable 15, so that the mounting board 2 functions as a shield plate. Therefore, the function of the shield plate between the digital cable 15 and the analog cable 13 can be performed by using existing components, and the number of components can be reduced.
[0018]
At a position corresponding to the interval region 5 of the mounting board 2, a tunnel-like passage portion 17 for arranging the digital cable 15 is formed adjacent to the opening 16. As shown in FIG. 2, the passage 17 has a convex shape from the back side of the substrate 2 toward the front side. The length of the passage 17 is larger than the width of the analog cable 13 and the width of the connectors 11 and 12 thereof. Is also long enough. The height of the passage portion 17 is set so that the digital cable 15 pulled out from the opening 16 to the back side of the unit 1 can be stored without protruding to the back side of the unit 1. Since the passages 17 are arranged corresponding to the spacing regions 5, the height of the passages 17 can be set relatively freely without being restricted by the substrates 3 and 4. Therefore, the height of the passage portion 17 is set higher than the substrates 3 and 4, but may be set lower than the substrates 3 and 4.
[0019]
The tunnel-shaped passage portion 17 functions not only as a shield plate between the digital cable 15 and the analog cable 13 but also as a storage portion for storing the digital cable 15, so that the number of parts can be further reduced. .
[0020]
The analog cable 13 is disposed across the tunnel-like passage 17. Therefore, the connectors 11 and 12 are also fixed at positions facing each other with the tunnel-shaped passage portion 17 interposed therebetween.
[0021]
On the upper part of the second circuit board 4, a DIP switch 18 for performing various settings, a temperature sensor 19, and the like are arranged. Since the setting DIP switch 18 is disposed on the side opposite to the side on which the input / output terminals 6 of the substrate 4 are disposed, the setting operation is obstructed by the input / output terminals 6 and various cables connected thereto. Can be prevented.
[0022]
As shown in FIG. 3, the unit 1 configured as described above is mounted and used on the back of a digital display device, in this example, a liquid crystal display device 20 having a digital input.
[0023]
【The invention's effect】
As described above, according to the present invention, when an analog cable and a digital cable are arranged so as to overlap in a plane, noise leaking to the analog cable can be suppressed. Then, the structure can be realized using existing components, and the configuration can be simplified.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of the present invention.
FIG. 2 is a perspective view of the mounting board of the embodiment.
FIG. 3 is a perspective view of an apparatus equipped with the unit of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Interface circuit unit 2 Mounting board 3 First circuit board 4 Second circuit board 5 Spacing area 11 Connector 12 Connector 13 Analog cable 14 Connector 15 Digital cable 16 Opening 17 Passage

Claims (4)

A first circuit board having an analog output section, a second circuit board having an analog input section and a digital output section, and a metal mounting board for fixing the first and second circuit boards at an interval from each other; An analog cable that connects the analog output unit and the analog input unit through a space area of the circuit board; and a digital cable that is connected to the digital output unit and that is arranged with a planar overlap with the analog cable. An interface circuit unit, wherein an opening communicating between the front and back of the mounting board is provided in the space region of the mounting board, and the digital cable is led out to the back side of the mounting board from the opening. 2. The interface circuit unit according to claim 1, wherein the opening is formed in a region avoiding a planar overlap with the analog cable. 3. The interface circuit unit according to claim 1, wherein a tunnel-like passage portion for arranging the digital cable is formed adjacent to the opening of the mounting board. The first and second circuit boards are fixed so that an analog output section of the first circuit board and an analog input section of the second circuit board face each other with the tunnel-shaped passage section interposed therebetween. The interface circuit unit according to claim 3, wherein

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