CN203057384U - High-frequency tuner and television set-top box - Google Patents
High-frequency tuner and television set-top box Download PDFInfo
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- CN203057384U CN203057384U CN 201320008686 CN201320008686U CN203057384U CN 203057384 U CN203057384 U CN 203057384U CN 201320008686 CN201320008686 CN 201320008686 CN 201320008686 U CN201320008686 U CN 201320008686U CN 203057384 U CN203057384 U CN 203057384U
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Abstract
The embodiment of the utility model discloses a high-frequency tuner and a television set-top box, and relates to the field of RF circuit. The interference of the power frequency voltage signals on the protection circuit can be shielded, thus the working performance of the television set-top box can be improved. The high-frequency tuner provided by the embodiment of the utility model comprises an RF cable interface, a first capacitor, a protection circuit, a filter and a first inductor, wherein an RF cable is connected with the RF cable interface, the first capacitor is located between the RF cable interface and the filter, one end of the protection circuit is located between the first capacitor and the filter, the other end is grounded, and the first inductor is connected with the protection circuit in parallel.
Description
Technical field
The utility model relates to the radio circuit field, relates in particular to a kind of high-frequency tuner and television set top box.
Background technology
High-frequency tuner is called channel selector again, be commonly called as tuner, be positioned at the front end of television set top box, be connected with radio frequency cable, be used for the received RF cable and carried the working signal of television channel program information, the working signal that receives is carried out sending in the television set after operation such as mixing is amplified in filtering then.
Comprise in the high-frequency tuner: cell mesh such as radio frequency cable interface, protection circuit, filter, tuner.Protection circuit is positioned at the front end of high-frequency tuner, is mainly used in clamping down on the voltage of the input signal in the radio frequency cable, prevents from surpassing the maximum input signal that allows to receive voltage and enters, and other circuit of protection high-frequency tuner inside are avoided damage.
Yet the inventor finds that in R﹠D process there is following defective at least in prior art: the television set top box system is also earth-free in the course of the work, therefore, can produce power-frequency voltage in radio frequency cable.As shown in Figure 1, Fig. 1 is the indicatrix of the power-frequency voltage that produces in the floating neutral system, and the transverse axis of Fig. 1 is represented the time, and the longitudinal axis of Fig. 1 is represented the magnitude of voltage of power-frequency voltage.The frequency of China's power-frequency voltage is that 50Hz, magnitude of voltage are 220V.Therefore, except the working signal of carrying television channel program information, also can comprise the power-frequency voltage signal that produces in the floating neutral system in the radio frequency cable input signals transmitted.If do not do respective handling, described power-frequency voltage signal can produce working signal and disturb, and finally influences the display quality of television signal.
Summary of the invention
Embodiment of the present utility model technical problem to be solved is to provide a kind of high-frequency tuner and television set top box, can shield the interference that the power-frequency voltage signal produces protection circuit, thereby improves the service behaviour of television set top box.
The application's one side, a kind of high-frequency tuner is provided, comprise: be used for receiving the radio frequency cable interface of first input signal, described first input signal comprises the power-frequency voltage signal that radio frequency cable produces, and described radio frequency cable is connected with described radio frequency cable interface;
First electric capacity that is used for the described first input signal direct current signal of filtering;
Protection circuit for the magnitude of voltage of clamping down on described first input signal;
The filter that is used for the described first input signal noise signal of filtering;
Described first electric capacity is arranged between described radio frequency cable interface and the described filter, one end of described protection circuit is between described first electric capacity and described filter, other end ground connection, also comprise first inductance, described first inductance and described protection circuit are in parallel, and being used for derives ground connection with the described power-frequency voltage signal of described first input signal.
In first kind of possible implementation, described protection circuit is any one among bidirectional diode or atmospherical discharges diode or the transient voltage inhibition diode TVS.
In second kind of possible implementation, described high-frequency tuner also comprises: be used for the tuner of the operating frequency of the described first input signal working signal of demodulation, the input of described tuner is connected with the output of described filter.
In conjunction with first aspect, first kind or second kind of possible implementation, in the third possible implementation, the inductance value L of described first inductance satisfies 2 π * f*L 〉=800 Ω, and wherein, f is the operating frequency of working signal in described first input signal.
In conjunction with first aspect, the third possible implementation, in the 4th kind of possible implementation, when the operating frequency of working signal in described first input signal was 47MHz, described inductance was not less than 270nH.
In conjunction with first aspect, the third possible implementation, in the 5th kind of possible implementation, when the operating frequency of working signal in described first input signal was 860MHz, described inductance was not less than 15nH.
The application's one side again provides a kind of television set top box, comprises above-described high-frequency tuner.
The high-frequency tuner of the utility model embodiment and television set top box, by first inductance that is connected in parallel with protection circuit is set, utilize the feature of the logical low frequency resistance of inductance high frequency, the power-frequency voltage signal is derived ground connection, avoid the power-frequency voltage signal that protection circuit is produced and disturb, improved the service behaviour of television set top box.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, the accompanying drawing of required use is done to introduce simply in will describing embodiment below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the indicatrix of power-frequency voltage in the floating neutral system;
Fig. 2 is under the intact situation of screen, the test waveform at protection circuit place;
Fig. 3 is under the situation of screen breakage, the test waveform at protection circuit place;
Fig. 4 is the structural representation of the utility model embodiment medium-high frequency tuner.
Embodiment
A kind of high-frequency tuner and television set top box that the utility model embodiment provides can shield the interference that the power-frequency voltage signal produces protection circuit, thereby improve the service behaviour of television set top box.
In below describing, in order to illustrate rather than in order limiting, to have proposed the detail such as particular system structure, interface, technology, understand the utility model in order to cut thoroughly.Yet, not it will be clear to one skilled in the art that in having other embodiment of these details and can realize the utility model yet.In other situation, omit the detailed description to well-known device, circuit and method, in order to avoid unnecessary details hinders description of the present utility model.
The application's one side provides a kind of high-frequency tuner, as shown in Figure 4, comprising: radio frequency cable interface 1, first electric capacity 2, protection circuit 3, first inductance 4, filter 5.Wherein, radio frequency cable interface 1 is connected with radio frequency cable 10; Transmission has first input signal in the radio frequency cable 10.First input signal transmits in radio frequency cable 10, comprising: the power-frequency voltage signal that radio frequency cable produces, carried working signal, direct current signal and noise signal of television channel program information etc.
First electric capacity 2 is arranged between radio frequency cable interface 1 and the filter 4, and according to the logical characteristics that exchange the resistance direct current of electric capacity, first electric capacity 2 prevents that with the direct current signal filtering in first input signal described direct current signal from producing interference to working signal.In addition, first electric capacity 2 can also play a protective role, and prevents that surge voltage from producing impact to the high-frequency tuner internal circuit element.
One end of protection circuit 3 between first electric capacity 2 and filter 4, other end ground connection.Further, according to structure and the work characteristics of protection circuit, protection circuit 3 specifically can be: bidirectional diode, atmospherical discharges diode, transient voltage suppress diode (English: TransientVoltage Suppressor, abbreviation: TVS) etc.When the magnitude of voltage in first input signal during greater than maximum permissible voltage, protection circuit 3 just can conducting ground connection, prevents that the signal that surpasses maximum permissible voltage from entering, thus other inner electric elements of protection high-frequency tuner.
Being connected in parallel with protection circuit 3 arranges first inductance 4, and according to the characteristics of the logical low frequency resistance of inductance high frequency, first inductance 4 can be derived the power-frequency voltage signal ground connection and can not derive working signal.Need to prove that the frequency of power-frequency voltage is 50Hz, therefore, the power-frequency voltage signal belongs to low frequency signal, and inductance is very low to the low frequency signal impedance, is equivalent to path.Therefore, the power-frequency voltage signal can flow out and can not flow out by protection circuit 3 by first inductance 4.First inductance 4 is derived ground connection with the power-frequency voltage signal, has avoided the power-frequency voltage signal that protection circuit 3 is produced and has disturbed.
And first inductance 4 is for working signal, for instance, with transmission of digital cable video broadcasting (English: Digital Video Broadcasting Cable in the radio frequency cable, abbreviation: DVB-C) signal is example, the frequency range of DVB-C working signal is 47MHz～860MHz, and therefore, working signal belongs to high-frequency signal, inductance is very high to the high-frequency signal impedance, is equivalent to open circuit.Therefore first inductance 4 that is connected in parallel with protection circuit 3 can not derived working signal.
Need to prove that first inductance, 4 operation principles are to determine that according to the characteristic that the logical low frequency of inductance hinders high frequency therefore, the position of first inductance 4 can arrange as shown in Figure 4; In addition, described first inductance 4 also can arrange other positions, for example: in the left side of described protection circuit, be connected with described protection circuit parallel connection.
Any that need specify, as shown in Figure 2, Fig. 2 is under the intact situation of screen, the test waveform at protection circuit 3 places.Can see that it is comparatively level and smooth that handle the signal that generate through protection circuit 3 this moment, illustrates that interference is less in signal this moment.In fact, under the intact situation of the screen of radio frequency cable 10, the power-frequency voltage signal can (screen ground is the low impedance path place on the screen) flow out through screen ground in first input signal, and at this moment, the power-frequency voltage signal can not produce protection circuit and disturb; Then, as shown in Figure 3, Fig. 3 is under the situation of screen breakage, the test waveform at protection circuit 3 places.Can see, comprise a lot " burr " in the signal that this moment, protection circuit 3 processing generated, should " burr " represent violent change in the signal, illustrate that comprised a lot of noise jamming in the signal this moment.In fact, when the screen of radio frequency cable 10 occur damaged, for example: high-frequency tuner in installation process the screen breakage that cause because install improper; Perhaps the screen that produces because of aging circuit damages, make the power-frequency voltage signal to flow out by screen ground, at this moment, the power-frequency voltage signal can be come out by protection circuit 3 demodulation, and on the working signal in first input signal that is added to, the reception work of high-frequency tuner is exerted an influence.Therefore, first inductance 4 that protection circuit 3 is connected in parallel is set, can avoids above-mentioned power-frequency voltage signal by the generation of the situation of protection circuit 3 demodulation, improve the service behaviour of high-frequency tuner.
Further, also comprise in the high-frequency tuner: tuner 6, for the operating frequency of the described first input signal working signal of demodulation, the input of tuner 6 is connected with the output of filter 5.
The high-frequency tuner of the utility model embodiment, by first inductance that is connected in parallel with protection circuit is set, utilize the feature of the logical low frequency of inductance resistance high frequency, the power-frequency voltage signal is derived, avoid the power-frequency voltage signal that protection circuit is produced and disturb, improved the service behaviour of television set top box.
As a kind of comparatively preferred implementation of the present utility model, according to the impedance computation formula of inductance, impedance=2 π * f*L.As impedance 〉=800 Ω, the decay that working signal in the radio frequency cable is produced is very little, can this decay be not more than 0.1dB after the calculating.Can think, the working signal when first inductance 4 satisfies above-mentioned condition in the not conducting radio frequency cable, first inductance 4 can not exert an influence to working signal in the radio frequency cable.Therefore, this implementation is a kind of comparatively preferably selection.
Need to prove that the condition of mentioning in implementation of the present utility model that first inductance satisfied only is a kind of more excellent selection, in concrete use, inductance value can be arranged according to actual conditions by the technical staff, does not do restriction at this.
Further, as a kind of specific implementation of the present utility model, be example with the input signal of DVB-C standard.DVB-C is the english abbreviation of digital cable TV broadcasting, and the frequency range of its input signal is: 47MHz～860MHz.Be example with " 47MHz " working signal frequency, first input signal in this moment radio frequency cable comprises working signal and " 50Hz " power-frequency voltage signal of " 47MHz ".When first inductance 4 was not less than " 270nH ", the calculating inductance 4 of can winning was not less than 800 Ω to the impedance of the working signal of " 47MHz ", and 4 pairs of working signals of first inductance this moment present the high impedance effect; And calculate the inductance 4 of to win the impedance of " 50Hz " power-frequency voltage signal is approximately 0.Thus, first inductance is derived ground connection with the power-frequency voltage signal and can not exerted an influence to working signal.
As another kind of specific implementation of the present utility model, be example with " 860MHz " working signal frequency, first input signal in the radio frequency cable comprises working signal and " 50Hz " power-frequency voltage signal of " 860MHz " at this moment.When first inductance 4 was not less than " 15nH ", the calculating inductance 4 of can winning was not less than 800 Ω to the impedance of the working signal of " 860MHz ", and this moment, inductance presented the high impedance effect to working signal; Can this first inductance 4 impedance of " 50Hz " power-frequency voltage signal be approximately 0 and calculate.Thus, inductance is derived ground connection with the power-frequency voltage signal and can not exerted an influence to working signal.
The input circuit of the utility model embodiment, by first inductance that is connected in parallel with protection circuit is set, utilize the feature of the logical low frequency of inductance resistance high frequency, the power-frequency voltage signal is derived, avoid the power-frequency voltage signal that protection circuit is produced and disturb, improved the service behaviour of television set top box.
The application provides a kind of television set top box on the other hand, comprises above-mentioned high-frequency tuner.Wherein the structure of high-frequency tuner and operation principle be with above-mentioned execution mode, do not do at this and give unnecessary details.In addition, other structure divisions of television set top box can be not described in detail at this this paper with reference to prior art.
The high-frequency tuner of the utility model embodiment, first inductance that in the input circuit of high-frequency tuner, is connected in parallel by setting and protection circuit, utilize the feature of the logical low frequency of inductance resistance high frequency, the power-frequency voltage signal is derived, avoid the power-frequency voltage signal that protection circuit is produced and disturb, improved the service behaviour of television set top box.
The above; it only is embodiment of the present utility model; but protection range of the present utility model is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the utility model discloses; can expect easily changing or replacing, all should be encompassed within the protection range of the present utility model.Therefore, protection range of the present utility model should be as the criterion with the protection range of described claim.
Claims (7)
1. high-frequency tuner comprises:
Be used for receiving the radio frequency cable interface of first input signal, described first input signal comprises the power-frequency voltage signal that radio frequency cable produces, and described radio frequency cable is connected with described radio frequency cable interface;
First electric capacity that is used for the described first input signal direct current signal of filtering;
Protection circuit for the magnitude of voltage of clamping down on described first input signal;
The filter that is used for the described first input signal noise signal of filtering;
Described first electric capacity is arranged between described radio frequency cable interface and the described filter, one end of described protection circuit is between described first electric capacity and described filter, other end ground connection, it is characterized in that, also comprise first inductance, described first inductance and described protection circuit are in parallel, and being used for derives ground connection with the described power-frequency voltage signal of described first input signal.
2. high-frequency tuner according to claim 1 is characterized in that, described protection circuit is any one among bidirectional diode or atmospherical discharges diode or the transient voltage inhibition diode TVS.
3. high-frequency tuner according to claim 1 is characterized in that, also comprises: be used for the tuner of the operating frequency of the described first input signal working signal of demodulation, the input of described tuner is connected with the output of described filter.
4. according to each described high-frequency tuner of claim 1-3, it is characterized in that the inductance value L of described first inductance satisfies 2 π * f*L 〉=800 Ω, wherein, f is the operating frequency of working signal in described first input signal.
5. high-frequency tuner according to claim 4 is characterized in that, when the operating frequency of working signal in described first input signal was 47MHz, described inductance was not less than 270nH.
6. high-frequency tuner according to claim 4 is characterized in that, when the operating frequency of working signal in described first input signal was 860MHz, described inductance was not less than 15nH.
7. a television set top box is characterized in that, comprises each described high-frequency tuner of claim 1-6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320008686 CN203057384U (en) | 2013-01-08 | 2013-01-08 | High-frequency tuner and television set-top box |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320008686 CN203057384U (en) | 2013-01-08 | 2013-01-08 | High-frequency tuner and television set-top box |
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| CN203057384U true CN203057384U (en) | 2013-07-10 |
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| CN 201320008686 Expired - Fee Related CN203057384U (en) | 2013-01-08 | 2013-01-08 | High-frequency tuner and television set-top box |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103888760A (en) * | 2014-03-19 | 2014-06-25 | 深圳市九洲电器有限公司 | Set top box radiation and video quality debugging method and device |
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2013
- 2013-01-08 CN CN 201320008686 patent/CN203057384U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103888760A (en) * | 2014-03-19 | 2014-06-25 | 深圳市九洲电器有限公司 | Set top box radiation and video quality debugging method and device |
| CN103888760B (en) * | 2014-03-19 | 2016-01-20 | 深圳市九洲电器有限公司 | A kind of Set Top Box radiation and video quality adjustment method and device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20180212 Address after: California, USA Patentee after: Tanous Co. Address before: 518129 Longgang District, Guangdong, Bantian HUAWEI base B District, building 2, building No. Patentee before: HUAWEI DEVICE Co.,Ltd. Effective date of registration: 20180212 Address after: California, USA Patentee after: Global innovation polymerization LLC Address before: California, USA Patentee before: Tanous Co. |
|
| 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: 20130710 Termination date: 20220108 |