CN203313304U

CN203313304U - High-voltage isolation protective device for coaxial cable

Info

Publication number: CN203313304U
Application number: CN2013202861307U
Authority: CN
Inventors: 陈超; 王正卿
Original assignee: ROUTON ELECTRONIC CO Ltd
Current assignee: ROUTON ELECTRONIC CO Ltd
Priority date: 2013-05-23
Filing date: 2013-05-23
Publication date: 2013-11-27
Anticipated expiration: 2023-05-23

Abstract

The utility model provides a high-voltage isolation protective device for a coaxial cable. The high-voltage isolation protective device comprises a coaxial cable, an F-type connector, a feed-through capacitor, a digital working ground and a protection ground. The coaxial cable comprises a central signal line and an outer shielding layer. After the outer shielding layer at one end of the coaxial cable is exposed by peeling, the coaxial cable passes through the feed-through capacitor. An inner pole of the feed-through capacitor and the peeled outer shielding layer of the coaxial cable are welded to connect with the protection ground. An outer pole of the feed-through capacitor is connected with the digital working ground. The other end of the coaxial cable is connected with the F-type connector. In the use of a set top box or a digital television adopting the high-voltage isolation protective device, when a CATV network is abnormally grounded, the set top box or the digital television can still work normally with little insertion loss, and television signals can be received normally, or display can be carried out normally while not being affected. The high-voltage isolation protective device is also available for other high-voltage isolation and occasions requiring little signal attenuation.

Description

A kind of coaxial cable high-voltage isolation protective device

Technical field

The utility model relates to electronic circuit technology, in particular, is a kind of isolating and protecting device of the access of the digital catv signal for Set Top Box or Digital Television.

Background technology

Set Top Box or Digital Television, generally in the cable television network (CATV net) that the access of digital catv signal input is outside, current CATV net adopts coaxial cable to carry out transmission of digital signals, and coaxial cable consists of the holding wire at center and the screen of outside parcel.When the user watched cable TV by Set Top Box or digital television access catv network, holding wire was communicated with the radiofrequency signal receiving terminal of television set or Set Top Box, and screen is communicated with the power supply ground of television set or Set Top Box.When some television set or Set Top Box were ground wire grounded by electrical network, the ground wire of CATV cable TV signal just directly had been communicated with the electrical network ground wire.

In the ideal situation, the ground wire of CATV cable TV signal is communicated with the electrical network ground wire, can be not influential to the normal operation of Set Top Box or Digital Television.But in actual application environment, impact due to various factorss such as region, weather (as thunder and lightning) and grounding requirements, the desirable ground connection of the coaxial cable shielding layer of CATV net can not be guaranteed, and between the ground wire of electrical network ground wire and CATV cable TV signal, may have potential difference and forms abnormal voltage.In this state, if, by Set Top Box or Digital Television access CATV net, can form closed-loop path between coaxial cable, Set Top Box (or Digital Television), conduction casing and ac power cable, produce abnormal current.At the wire signal access terminal place that contact resistance is arranged, will cause heating like this, even ignite or burn terminal neighbouring plug, circuit, cause normally rating, also may cause accidental loss.In prior art, also there is the input of CATV cable TV signal to adopt common Capacitor apart scheme, but all very large to the decay of high-frequency signal, this problem is also not obvious when the signal of cable TV is relatively good, when cable TV signal is more weak, can cause and can not normally receive cable TV signal, cause television image that more " mosaic " phenomenon is arranged, not use in batches so be suitable on product.

In addition, be isolated in the technical requirement that also must meet mandatory national standards GB 8898-2011 between the protection of cable digital TV coaxial cable ground and digital operation ground, namely realize and withstand voltage can reaching is greater than DC500V.

Summary of the invention

The problems referred to above that exist in order to solve prior art; the utility model purpose is provides a kind of coaxial cable high-voltage isolation protective device; even reach CATV net ground connection when undesired; also can protect Set Top Box (or digital television) can trouble free service simultaneously; little to high frequency signal attenuation is that insertion loss is little, can receive or play normal TV signal.

In order to achieve the above object, the utility model has adopted following technical scheme: a kind of coaxial cable high-voltage isolation protective device, comprise coaxial cable, F type joint, feedthrough capacitor, digital operation ground and protection ground, described coaxial cable comprises the holding wire at center and the screen of outside parcel, after stripping out, coaxial cable one end outside screen passes feedthrough capacitor, the screen stripped out of the interior utmost point of feedthrough capacitor and coaxial cable is partly welded to rear access protection ground, the outer utmost point of feedthrough capacitor is connected with digital operation ground, another termination of coaxial cable F type joint, as the cable TV signal input interface.Facilitate the user to access cable TV network.

Perfect as to technique scheme; the utility model can also further be taked following technical measures: be provided with one group of isolation capacitance between described protection ground and digital operation ground; for supplementing feedthrough capacitor; after described coaxial cable passes feedthrough capacitor; isolation capacitance of its center holding wire series connection access, as the insulation blocking of holding wire.

The one group of isolation capacitance arranged between described protection ground and digital operation ground comprises two isolation capacitances, between two isolation capacitances access protection in parallel ground and digital operation ground.

Beneficial effect: adopt Set Top Box of the present utility model (or digital television); can realize the effective isolation between the protection ground of cable digital TV coaxial cable and Set Top Box (or digital television) digital operation ground; through test; withstand voltagely can reach AC700V; and in the operating frequency range of cable digital TV; the insertion loss that adds this spacer assembly to produce is less than 1dB, can guarantee normal reception and the use of cable digital TV.Therefore; this device not only can play the effect of safeguard protection; and can guarantee normal reception and the use of cable digital TV; namely preferably resolve transmission bandwidth 10-1000MHz; insertion loss≤2dB; the high-voltage isolation protective problem of the application scenario of withstand voltage >=500v, promoted product to growth requirement low-cost, the multifunction aspect.

The accompanying drawing explanation

Fig. 1 is principle schematic of the present utility model;

Fig. 2 is a specific embodiment of the present utility model;

Embodiment

Below in conjunction with accompanying drawing, the utility model is further illustrated as follows: as shown in Figure 1; the utility model comprises coaxial cable 2(band F type joint 1); an isolation capacitance 8 of holding wire series connection; for the feedthrough capacitor 4 on insulation blocking ground 12 and digital operation ground 13, the one group isolation capacitance 11 in parallel with feedthrough capacitor 4.

Below in conjunction with Fig. 2, a specific embodiment is described: it is the coaxial cable 2 of 75 ohm that this embodiment adopts characteristic impedance; model is RG179; coaxial cable 2 one end welding F type joints 1; coaxial cable 2 other ends are peeled external insulation off; the holding wire 7 that exposes screen 6 and center; again coaxial cable 2 is passed to the endoporus of feedthrough capacitor 4, by the interior utmost point of feedthrough capacitor 45 and rear protection ground 12, the i.e. ground wire of cable TV signal of forming of screen 6 welding of coaxial cable.The outer utmost point 10 of feedthrough capacitor 4 is welded on the digital operation ground 13 of Set Top Box (or digital television) circuit board 9.So, just realized the isolation on protection ground 12 and digital operation ground 13, simultaneously, feedthrough capacitor 4 has guaranteed coaxial cable 2 good buffer action all on the whole radial circumference, has reduced insertion loss.

For insertion loss in the operating frequency range that further reduces whole cable digital TV; between protection ground 12 and digital operation ground 13, added by one group of isolation capacitance 11; isolation capacitance 11 is comprised of the ceramic condenser of two parallel connections, with doing supplementing feedthrough capacitor 4.Concrete methods of realizing is that the end face 3 of the end face 3(feedthrough capacitor 4 of feedthrough capacitor 4 is connected with the interior utmost point 5) with the pad on protection ground 12 above circuit board 9, weld; between protection ground 12 and digital operation ground 13 on isolation capacitance 11 connecting circuit boards 9 that formed by the ceramic condenser of two parallel connections, realized that the isolation on protection ground 12 and digital operation ground 13 supplements.Holding wire 7 is welded on the pad of circuit board 9, and then series connection access ceramic condenser 8, as the isolation to holding wire.

Ceramic condenser

8 and 11 all is welded on circuit board 9.

This example is in transmission bandwidth 5～1000MHz scope, and insertion loss is less than 1dB, isolates the withstand voltage AC700V that is greater than, and can guarantee normal reception and the use of cable digital TV.The utility model also is applicable to other needs the high pressure isolation, also needs to guarantee that signal has the occasion of low insertion loss simultaneously.

Claims

1. coaxial cable high-voltage isolation protective device; it is characterized in that comprising coaxial cable; F type joint; feedthrough capacitor; digital operation ground and protection ground; described coaxial cable comprises the holding wire at center and the screen of outside parcel; after stripping out, coaxial cable one end outside screen passes feedthrough capacitor; the screen stripped out of the interior utmost point of feedthrough capacitor and coaxial cable is partly welded to rear access protection ground; the outer utmost point of feedthrough capacitor is connected with digital operation ground; another termination of coaxial cable F type joint, as the cable TV signal input interface.

2. coaxial cable high-voltage isolation protective device according to claim 1; it is characterized in that: be provided with one group of isolation capacitance between described protection ground and digital operation ground; for supplementing feedthrough capacitor; after described coaxial cable passes feedthrough capacitor; isolation capacitance of its center holding wire series connection access, as the insulation blocking of holding wire.

3. coaxial cable high-voltage isolation protective device according to claim 2; it is characterized in that: the one group of isolation capacitance arranged between described protection ground and digital operation ground comprises two isolation capacitances, the access protection in parallel of two isolation capacitances and digitally between.