JPH10200915A - Noise reducing device of television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically reduce black lines in an image and video disturbance, by providing wires that are connected to a cathode-ray tube with a noise filter. SOLUTION: A noise eliminating filter 6 is attached to wires 8 to 10 that connect a printed circuit 4 and a main printed circuit 5. Five lines in all, i.e., a bundle of 3 lines of primary color signal carrier lines 8 from a color signal reproducing circuit 7, a signal voltage electric line 9 and an earth cable 10, are connected between the printed circuits 4 and 5 through each connection point. The filter 6 is almost cylindrical, has an internal diameter that is large enough for plural wires 8 to 10 to be inserted through, is constituted of ferrite material and is provided with a thin slit along a longitudinal direction, and when the slit is opened and the five wires 8 to 10 are inserted, the slit is closed by elastic restoring force. Then, the filter is easily arranged halfway at the wires even after the circuits 4 and 5 are connected by the wires 8 to 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reducing noise in a television receiver, and more particularly to a technique for reducing noise in a television receiver provided with a filter suitable for removing noise generated in a color image of a color television. Related to the device.

[0002]

2. Description of the Related Art In a color television receiver, each part of a circuit is an IC
For example, a chroma IC of a color signal reproducing circuit for outputting a primary color signal to be applied to a cathode ray tube, a high voltage circuit for driving the cathode ray tube, and an IC of a deflection circuit are printed on a printed circuit board called a main substrate. It is installed in. An individual printed circuit board is also provided on the cathode ray tube side. The printed circuit board is connected to a carrier line of a primary color signal wired from the chroma IC of the main board, an output line from a drive circuit, and the like. It is supposed to be.

[0003]

By the way, a television receiver in which each part of the circuit is integrated on a printed circuit board as described above,
It became more susceptible to external radio waves and contributed to the noise appearing in CRT images. In particular, when the main board and the circuit components on which the chroma IC and the drive circuit IC are mounted are affected by external radio waves,
There were problems such as black streaks in the image and distorted images. For this reason, in the past, direct noise countermeasures were taken for various ICs, electronic components, and the like on the printed circuit board, but there was no remarkable effect and this was a major problem in circuit integration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a noise filter on a wiring connected to a cathode ray tube to remove noise to prevent black streaks from appearing in a picture of the cathode ray tube and disturb the image. It is an object of the present invention to provide a noise reduction device for a television receiver that can significantly reduce noise.

[0005]

According to a first aspect of the present invention, a wiring board on which a chroma integrated circuit or the like is mounted and a wiring board provided on a receiver are provided. It is characterized in that a plurality of wirings composed of primary color signal carrier lines, voltage transmission lines and ground lines to be connected are passed through a cylindrical filter made of a ferrite core. Further, according to the present invention, a pair of vertical deflection signal carrying lines for connecting a wiring board on which a vertical deflection circuit or the like is mounted and a deflection yoke on the receiver side are formed of a cylindrical ferrite core. It is characterized by passing through a filter.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a noise reduction device for a television receiver according to the present invention. This television receiver is a popular type color television and has a color cathode ray tube 1 housed in a cabinet.
A noise reduction filter 6 is configured by attaching a noise removing filter 6 to wirings 8 to 10 connecting the CRT printed board 4 and the main printed board 5 provided on the side. The color cathode ray tube 1 has a deflection yoke 3 and a purity magnet mounted on a neck portion, and the printed circuit board 4 mounted on a base 2 side.

[0007] The main printed circuit board 5 includes various circuits by IC.
A plurality of wirings are connected to connection points of the wiring pattern. On the main printed circuit board 5, a chroma IC of a color signal reproducing circuit 7 for outputting a primary color signal to be applied to the color CRT 1, an IC of a drive circuit such as a high voltage circuit and a deflection circuit for driving the color CRT 1, and the like are mounted. Between the main printed circuit board 5 and the printed circuit board 4, three bundles of primary color signal carrying lines 8 from the color signal reproducing circuit 7, a signal voltage transmission line 9, and a ground line via connection points. A total of ten 10 cables are connected.

The filter 6 has a substantially cylindrical shape and an inner diameter through which a plurality of wirings 8 to 10 can be inserted, and is formed of a ferrite material. The filter 6 has a narrow cut along the length direction. When the cut is opened and the five wirings 8 to 10 are inserted, the cut is closed by elastic restoring force. Therefore,
Even after the connection between the main printed circuit board 5 and the printed circuit board 4 by the wirings 8 to 10, the filter 6 can be easily arranged in the middle of the wiring. As described above, when the wirings 8 to 10 are passed through the filter 6, noise included in a signal transmitted from the main printed circuit board 5 to the printed circuit board 4 is removed, and black streaks appear in the image of the CRT 1 The problem of turbulence is greatly improved. In addition, the noise of the image of the cathode ray tube 1 is easily affected by noise.
As a result of placing the television receiver provided with the filter 6 in an interference wave of 50 MHZ and evaluating the immunity, noise due to the interference wave can be efficiently removed, and a black streak appears in the image or the image is disturbed. It became possible to almost eliminate the influence of noise.

FIG. 2 is a schematic configuration diagram showing a noise reduction device for a television receiver according to another embodiment of the present invention.
The noise reduction device of this television receiver is configured by attaching the same filter 6 as shown in FIG. 1 to a carrier line 15 connecting the main printed circuit board 5 and the deflection yoke 3 on the side of the color cathode ray tube 1 to constitute the noise reduction device. It is. The IC of the deflection circuit 11 constituting the drive circuit is mounted on the main printed circuit board 5 as described above. The horizontal and vertical deflection circuits 12, 13 of the deflection circuit 11
The pair of transport lines 14 and 15 are connected to the deflection yoke 3 of the cathode ray tube 1 respectively. The two transport lines 15 from the vertical deflection circuit 13 pass through the filter 6. The pair of transport lines 15 is wound once around the filter 6 in order to increase the noise reduction effect. When the carrier line 15 is passed through the filter 6 as described above, noise included in a signal transmitted from the main printed circuit board 5 to the vertical deflection yoke 3 is efficiently removed, and a black streak appears in the image of the CRT 1. And the problem of distorted images is greatly improved. Also in this case, the immunity is evaluated by giving jamming waves in a frequency band where noise is likely to affect the image, and as a result, the jamming waves can be efficiently removed.
The effect of noise that appeared in the image was almost eliminated.

[0010]

As described above, according to the first aspect of the present invention, a primary color signal carrier line for connecting a wiring board on which a chroma integrated circuit or the like is mounted and a wiring board provided on a receiver side. , Multiple wires consisting of voltage transmission line and ground line,
By passing through the cylindrical filter 6 made of a ferrite core, noise included in the signal transmitted from the chroma integrated circuit side to the receiver side is removed. This has the effect of greatly reducing the problem of disturbance. According to a second aspect of the present invention, there is provided a cylindrical filter comprising a ferrite core and a pair of vertical deflection signal carrier lines connecting a wiring board on which a vertical deflection circuit and the like are mounted and a deflection yoke on the receiver side. By passing through 6, the noise contained in the signal transmitted from the vertical deflection circuit side to the vertical deflection yoke side is efficiently removed, so that the problem of black streaks in the picture of the CRT or disturbing the image is greatly reduced. There is an effect that can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a noise reduction device of a television receiver according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a noise reduction device of a television receiver according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiver 4 Wiring board 5 Wiring board 6 Filter 8 Wiring

Claims (2)

[Claims] 1. A plurality of wirings consisting of a primary color signal carrier line, a voltage transmission line, and a ground line for connecting a wiring substrate on which a chroma integrated circuit or the like is mounted and a wiring substrate provided on a receiver side, A noise reduction device for a television receiver, which is passed through a cylindrical filter made of a ferrite core. 2. A pair of vertical deflection signal carrier lines for connecting a wiring board on which a vertical deflection circuit and the like are mounted and a deflection yoke on a receiver side are passed through a cylindrical filter made of a ferrite core. A noise reduction device for a television receiver.