CN207884798U - A kind of radio-frequency interface circuit of cable digital TV set-top box circuit - Google Patents
A kind of radio-frequency interface circuit of cable digital TV set-top box circuit Download PDFInfo
- Publication number
- CN207884798U CN207884798U CN201721864328.3U CN201721864328U CN207884798U CN 207884798 U CN207884798 U CN 207884798U CN 201721864328 U CN201721864328 U CN 201721864328U CN 207884798 U CN207884798 U CN 207884798U
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- top box
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Abstract
The utility model belongs to set-top box support circuit technical field, more particularly to a kind of radio-frequency interface circuit of cable digital TV set-top box circuit, isolation circuit is connected between one RF output end of two distributor and its another RF output end, the utility model solves the prior art, and there are set-top boxes in the case that cold, back wave can influence radiofrequency signal, the problem of declining so as to cause image clearly quality, with improving picture quality, attenuating is good, reduce interference of the back wave to radiofrequency signal, be conducive to promote the advantageous effects of one-way set-top box.
Description
Technical field
The utility model belongs to set-top box support circuit technical field more particularly to a kind of cable digital TV set-top box electricity
The radio-frequency interface circuit on road.
Background technology
It is a kind of household electrical appliances for extending functions of television set currently, set-top box refers to the box on television set top, set-top box is according to connecing
The signal kinds of receipts are divided into analog set top and top box of digital machine, and analog set top receives analog signal, and top box of digital machine receives
Digital signal, top box of digital machine are a kind of multimedia terminals, there is the hardware architecture similar to home computer and dedicated reality
When operating system, there are set-top boxes for the prior art in the case that cold, and back wave can influence radiofrequency signal, so as to cause figure
The problem of declining as clear quality.
Utility model content
The utility model provides a kind of radio-frequency interface circuit of cable digital TV set-top box circuit, to solve above-mentioned background
It proposing the prior art in technology there are set-top boxes in the case that cold, back wave can influence radiofrequency signal, so as to cause
The problem of image clearly quality declines.
The technical issues of the utility model is solved is realized using following technical scheme:A kind of cable digital TV machine top
The radio-frequency interface circuit of box circuit, including two distributors, the two distributors input are connected to single hole set-top box, and one radio frequency is defeated
Go out and be connected to tuner, another radio frequency output is connected to the ports RF of television set, and the tuner output is connected to comprehensive solution
Code device, the synthetic decoder video output are connected to the video port of television set, and audio output is connected to the sound of television set
Frequency port connects isolation circuit between one RF output end of two distributor and its another RF output end.
Further, the isolation circuit isolation loss is more than 22dB.
Further, the tuner input impedance is less than 100 Ω.
Advantageous effects:
1, this patent is connected to single hole set-top box using two distributor input, and the output of one radio frequency is connected to high frequency
Head, another radio frequency output are connected to the ports RF of television set, and the tuner output is connected to synthetic decoder, the synthesis
Decoder video, which exports, is connected to the video port of television set, and audio output is connected to the audio port of television set, and described two
Isolation circuit is connected between one RF output end of distributor and its another RF output end, due to two distributors, an output
End connects with tuner, and under power blackout situation, the input impedance of tuner is not 75 ohm, destroys matching transmission state, production
In raw reflective wave transmission to display terminal, image definition is made to decline, back wave is transmitted from this output end of two distributors
To another output end, enter in machine by the radio frequency socket of display terminal, when between two output ends of two distributors every
When from loss not less than 22dB, influence of the back wave to image definition can be better, to improve picture quality.
2, this patent is less than 100 Ω using the tuner input impedance, due to the impedance using 75-100 Ω, to reflection
Wave has preferable attenuating.
3, this patent connects and is isolated using between the RF output end and its another RF output end of two distributor
Circuit reduces interference of the back wave to radiofrequency signal.
4, this patent is conducive to promote one-way set-top box in wired city TV's Digitization Project.
Description of the drawings
Fig. 1 is a kind of module map of the radio-frequency interface circuit of cable digital TV set-top box circuit of the utility model.
Specific implementation mode
The utility model is described further below in conjunction with attached drawing:
In figure:Bis- distributors of 1-, 2- single hole set-top boxes, 3- tuners, 4- television sets, 5- synthetic decoders, 6- isolation electricity
Road.
Embodiment:
The present embodiment:As shown in Figure 1, a kind of radio-frequency interface circuit of cable digital TV set-top box circuit, including two points
Orchestration 1, the input of two distributor 1 are connected to single hole set-top box 2, and the output of one radio frequency is connected to tuner 3, another radio frequency
Output is connected to the ports RF of television set 4, and the output of the tuner 3 is connected to synthetic decoder 5, and the synthetic decoder 5 regards
Frequency output is connected to the video port of television set 4, and audio output is connected to the audio port of television set 4, two distributor 1
A RF output end and its another RF output end between connect isolation circuit 6.
6 isolation loss of the isolation circuit is more than 22dB.
3 input impedance of the tuner is less than 100 Ω.
Operation principle:
This patent is connected to single hole set-top box by using two distributor input, and the output of one radio frequency is connected to high frequency
Head, another radio frequency output are connected to the ports RF of television set, and the tuner output is connected to synthetic decoder, the synthesis
Decoder video, which exports, is connected to the video port of television set, and audio output is connected to the audio port of television set, and described two
Isolation circuit is connected between one RF output end of distributor and its another RF output end, due to two distributors, an output
End connects with tuner, and under power blackout situation, the input impedance of tuner is not 75 ohm, destroys matching transmission state, production
In raw reflective wave transmission to display terminal, image definition is made to decline, back wave is transmitted from this output end of two distributors
To another output end, enter in machine by the radio frequency socket of display terminal, when between two output ends of two distributors every
When from loss not less than 22dB, influence of the back wave to image definition can be better, and the utility model solves the prior art
There are set-top boxes in the case that cold, and back wave can influence radiofrequency signal, is asked so as to cause what image clearly quality declined
Topic has and improves that picture quality, attenuating are good, reduce back wave to the interference of radiofrequency signal, are conducive to promote irreversible engine
The advantageous effects of top box.
Using the technical solution of the utility model or those skilled in the art technical solutions of the utility model inspiration
Under, similar technical solution is designed, and reach above-mentioned technique effect, it is to fall into the scope of protection of the utility model.
Claims (3)
1. a kind of radio-frequency interface circuit of cable digital TV set-top box circuit, which is characterized in that including two distributors, described two
Distributor input is connected to single hole set-top box, and the output of one radio frequency is connected to tuner, and another radio frequency output is connected to TV
The ports RF of machine, the tuner output are connected to synthetic decoder, and the synthetic decoder video output is connected to television set
Video port, audio output is connected to the audio port of television set, and a RF output end of two distributor is another with it
Isolation circuit is connected between one RF output end.
2. a kind of radio-frequency interface circuit of cable digital TV set-top box circuit according to claim 1, which is characterized in that
The isolation circuit isolation loss is more than 22dB.
3. a kind of radio-frequency interface circuit of cable digital TV set-top box circuit according to claim 1, which is characterized in that
The tuner input impedance is less than 100 Ω.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201721864328.3U CN207884798U (en) | 2017-12-27 | 2017-12-27 | A kind of radio-frequency interface circuit of cable digital TV set-top box circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201721864328.3U CN207884798U (en) | 2017-12-27 | 2017-12-27 | A kind of radio-frequency interface circuit of cable digital TV set-top box circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
CN207884798U true CN207884798U (en) | 2018-09-18 |
Family
ID=63504449
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201721864328.3U Expired - Fee Related CN207884798U (en) | 2017-12-27 | 2017-12-27 | A kind of radio-frequency interface circuit of cable digital TV set-top box circuit |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN207884798U (en) |
-
2017
- 2017-12-27 CN CN201721864328.3U patent/CN207884798U/en not_active Expired - Fee Related
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
GR01 | Patent grant | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180918 Termination date: 20181227 |