CN202918450U - Direct broadcasting satellite digital television set top box - Google Patents
Direct broadcasting satellite digital television set top box Download PDFInfo
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- CN202918450U CN202918450U CN 201220639379 CN201220639379U CN202918450U CN 202918450 U CN202918450 U CN 202918450U CN 201220639379 CN201220639379 CN 201220639379 CN 201220639379 U CN201220639379 U CN 201220639379U CN 202918450 U CN202918450 U CN 202918450U
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Abstract
The utility model discloses a direct broadcasting satellite digital television set top box, comprising a tuning unit and an audio/video decoding chip with a built-in satellite signal demodulator. The tuning unit receives direct broadcasting satellite radiofrequency signals which are performed down-conversion treatment and converted into baseband signals and are transmitted to the audio/video decoding chip to perform baseband signal demodulation and audio/video signal decoding; audio signals and video signals are restored and transmitted to an audio/video output terminal of a set top box. The direct broadcasting satellite digital television set top box employs an audio/video decoding chip of a built-in ABS demodulator to perform integrated design of a system circuit, which simplifies a circuit structure, shields interference, reduces wiring difficulty, space occupation of a circuit board and hardware costs of a whole machine, substantially improves a high frequency head demodulation performance, reduces production debugging difficulty, guarantees batch production consistency of set top box products and raises productive efficiency.
Description
Technical field
The utility model belongs to the apparatus of digital television receiving technical field, specifically, relates to a kind of circuit design of direct broadcasting satellite digital TV set-top box.
Background technology
Flourish along with the Digital Television cause, China has formed the situation of standing like the legs of a tripod of satellite, wired, ground three large digital television transfer modes.Present stage, wideband direct broadcast satellite TV broadcasting becomes more and more general, and China has had the satellite-signal transmission standard of complete independent intellectual property right, i.e. ABS-S standard at present.ABS direct broadcasting satellite digital TV set-top box for Chinese standard, the traditional design scheme of its product generally all is to adopt the syllogic circuit-mode design of tuner+ABS direct broadcasting satellite demodulation chip+audio/video decoder, its circuit is realized more loaded down with trivial details, the circuitry design is complicated, the wiring difficulty is large, and the circuit board size is wayward, and cost is higher, and production and debugging difficulty are large.
Summary of the invention
The purpose of this utility model is to provide a kind of direct broadcasting satellite digital TV set-top box, by simplifying the internal circuit design of set-top box, to reduce the wiring difficulty of circuit board, economize on hardware cost.
In order to solve the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of direct broadcasting satellite digital TV set-top box comprises tuned cell and the audio/video decoding chip that is built-in with the satellite-signal demodulator; Described tuned cell receives the direct broadcasting satellite radiofrequency signal, carry out converting baseband signal to after the down-converted, after transferring to decoding that described audio/video decoding chip carries out modulation demodulation and audio-video signal and processing, restore audio signal and the video signal transmission audio frequency and video lead-out terminal to the set-top box.
Wherein a kind of circuit design scheme as described tuned cell, in described tuned cell, be provided with satellite earth antenna and radiofrequency receiving chip, described satellite earth antenna receives the direct broadcasting satellite radiofrequency signal, and converting single core radio signal transmission to after described radiofrequency receiving chip carries out down-converted, the output base band signal transmission is to described audio/video decoding chip.
Preferably, described radiofrequency receiving chip single core radiofrequency signal that will receive converts the base band signal transmission of a pair of quadrature in phase to described audio/video decoding chip.
Further, described audio/video decoding chip transmits control command by the bus terminal of I2C bus connection radiofrequency receiving chip; And sub by the gain control end of its rf gain control pin connection radiofrequency receiving chip, the transmission gain control signal.
Another circuit design scheme as described tuned cell, in described tuned cell, be provided with tuner, the rf inputs of described tuner receives the direct broadcasting satellite radiofrequency signal, after down-converted, convert the baseband signal of a pair of quadrature in phase to, transfer to described audio/video decoding chip.
Further, described audio/video decoding chip transmits control command by the bus terminal of I2C bus connection tuner; And sub by the gain control end of its rf gain control pin connection radiofrequency receiving chip, the transmission gain control signal.
As the third circuit design scheme of described tuned cell, can in set-top box, realize the Design of Compatibility of two types of tuned cells, to make things convenient for research staff's choice for use.That is, lay two groups of tuned cells at the pcb board of set-top box, be provided with satellite earth antenna and radiofrequency receiving chip in one group of tuned cell therein, in other one group of tuned cell, be provided with tuner; Described audio/video decoding chip is connected corresponding connections of bus terminal with described radiofrequency receiving chip respectively by the I2C bus with tuner, selection is enabled wherein one group of tuned cell reception direct broadcasting satellite radiofrequency signal and carried out down-converted.
Further, described audio/video decoding chip transfers to respectively gain control end of radiofrequency receiving chip and tuner by its rf gain control pin outputing gain control signal, to the control that gains of radiofrequency receiving chip and tuner.
Further again, in described set-top box, be provided with two groups of crystal oscillating circuits, one group of crystal oscillating circuit connects described radiofrequency receiving chip, another group crystal oscillating circuit respectively with the corresponding connection with the audio/video decoding chip of described tuner, move required reference clock for each chip provides.
Preferably, described audio/video decoding chip is preferably with audio signal and vision signal after the reduction of the formal output of composite video broadcast singal CVBS, transfers to audio frequency and video lead-out terminal on the set-top box by its CVBS interface.
Compared with prior art, advantage of the present utility model and good effect are: direct broadcasting satellite digital TV set-top box of the present utility model adopts the audio/video decoding chip of built-in ABS demodulator to carry out the global design of circuit system, not only simplified circuit structure, shielded interference, reduced the wiring difficulty, dwindle the space hold to circuit board, reduced the hardware cost of complete machine; And significantly improved the tuner demodulation performance, and reduced the difficulty of producing debugging, guaranteed the consistency of set-top box product batch production, improved prouctiveness.
Description of drawings
In order to be illustrated more clearly in the technical scheme among the utility model embodiment, the below will do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art.Apparently, the accompanying drawing in the following describes 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 according to these accompanying drawings other accompanying drawing.
Fig. 1 is the schematic block circuit diagram of a kind of embodiment of the direct broadcasting satellite digital TV set-top box that proposes of the utility model;
Fig. 2 is the circuit theory diagrams of a kind of embodiment of radiofrequency receiving chip and peripheral circuit thereof among Fig. 1;
Fig. 3 is the circuit theory diagrams of a kind of embodiment of Fig. 1 making high frequency head and peripheral circuit thereof;
Fig. 4 is the circuit theory diagrams of a kind of embodiment of Fig. 1 middle pitch video decoding chip and peripheral circuit thereof.
Embodiment
Below in conjunction with the accompanying drawing among the utility model embodiment, the technical scheme among the utility model embodiment is clearly and completely described.Obviously, described embodiment only is a part of embodiment in the utility model, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making all other embodiment that obtain under the creative work prerequisite, all belong to the scope of the utility model protection.
For the advantage that makes technical solutions of the utility model is clearer, below in conjunction with drawings and Examples the utility model is explained.
Embodiment one, the direct broadcasting satellite digital TV set-top box of present embodiment is in order to simplify circuit design, adopt the System on Chip/SoC of high integration, namely be built-in with the satellite-signal demodulator audio/video decoding chip of (or claiming the ABS demodulator), the cooperation tuned cell carries out the system of set-top box complete machine, referring to shown in Figure 1, and then under the prerequisite of realization to the high-quality reception of direct broadcasting satellite radiofrequency signal, reduce the use of peripheral components, guaranteed the cost advantage of product.
In the present embodiment, described tuned cell can adopt two kinds of different circuit teaming methods: a kind of is to adopt satellite earth antenna to cooperate radiofrequency receiving chip to design described tuned cell, that is: reception antenna receives the direct broadcasting satellite radiofrequency signal via satellite, and after converting single core radiofrequency signal to, transfer to that radiofrequency receiving chip carries out that signal amplifies and down-converted after, convert extremely described audio/video decoding chip of base band signal transmission to.Described audio/video decoding chip at first utilizes its inner integrated ABS demodulator that the baseband signal that receives is carried out signal solution mediation channel-decoding, and then after generating audio and video data streams and doing further audio/video decoding processing, restore initial audio signal and vision signal, be sent to external television set by the audio frequency and video lead-out terminal that is arranged on the set-top box, realize thus the broadcast output of satellite feed.The second teaming method is directly to adopt tuner to cooperate the described tuned cell of simple periphery circuit design, that is: utilize an integrated tuner chip to receive the direct broadcasting satellite radiofrequency signal that TV station sends, after in the tuner chip, carrying out the amplification and down-converted of signal, convert baseband signal to, export described audio/video decoding chip to.After described audio/video decoding chip carries out the decoding processing of signal demodulation, channel-decoding and audio-video signal to the baseband signal that receives, restore original audio signal and vision signal, preferably the form with composite video broadcast singal CVBS transfers to the audio frequency and video lead-out terminal, realizes that to export television set to the selection of satellite programming is play.
Certainly, also can on the pcb board of set-top box, lay simultaneously two groups of tuned cells, namely cooperate first group of tuned cell of radiofrequency receiving chip establishment and the second group of tuned cell that cooperates peripheral circuit to set up by tuner by satellite earth antenna, two groups of tuned cells are connected the audio/video decoding chip that is built-in with the ABS demodulator by the I2C bus, select as required to enable one group of tuned cell by the audio/video decoding chip, finish reception and down-converted requirement to the direct broadcasting satellite radiofrequency signal, referring to shown in Figure 1.
Below in conjunction with Fig. 2-Fig. 4 the physical circuit assembling structure of described direct broadcasting satellite digital TV set-top box is explained in detail.
Fig. 2 is the annexation figure of radiofrequency receiving chip and peripheral circuit thereof.Wherein, RU1 is described radiofrequency receiving chip, its radio-frequency (RF) signal input end RFIP connects satellite earth antenna RF1 by band pass filter and the capacitance RC15 that is comprised of with electric capacity RC13 inductance RL1, RL2, receives single core radiofrequency signal of via satellite reception antenna RF1 conversion output.Be integrated with signal amplifier and low noise block downconverter LNB in the inside of described radiofrequency receiving chip RU1, the single core radiofrequency signal that receives is carried out that signal amplifies and after quadrature frequency conversion processes, convert the baseband signal of a pair of quadrature in phase to, transfer to described audio/video decoding chip U1.In the present embodiment, described baseband signal preferably occurs with the form of differential signal, be VIP, VIN, VQP, VQN, electric capacity RC14, RC18, RC21, RC19 via one tunnel series connection carries out after straight processing separately, transfer to baseband signal input pin P_ADC_VIN, P_ADC_VIP, P_ADC_VQN, the P_ADC_VQP of audio/video decoding chip U1, in conjunction with shown in Figure 4.
Fig. 3 is the annexation figure of tuner and peripheral circuit thereof.Wherein, T1 is described tuner, receive the direct broadcasting satellite radiofrequency signal that TV station sends by its rf inputs, and after carrying out frequency reducing and frequency-conversion processing, the baseband signal VIP, the VQP that export a pair of quadrature in phase transfers to audio/video decoding chip U1.In the present embodiment, be preferably the quadrature component of two single-ended format by baseband signal VIP, the VQP of tuner T1 output, transfer to respectively baseband signal input pin P_ADC_VIP, the P_ADC_VQP of audio/video decoding chip U1, utilize the internal circuit Auto-matching of audio/video decoding chip U1 to become the digital orthogonal baseband signal of difference form, to satisfy the inner ABS demodulator of audio/video decoding chip U1 to the demodulation requirement of baseband signal, in conjunction with shown in Figure 4.
Described audio/video decoding chip U1 at first separates the mediation channel-decoding to baseband signal VIN, VIP, VQN, the VQP that receives, and generates audio and video data streams; Then described audio and video data streams is carried out audio/video decoding, to restore original audio signal and vision signal, CVBS signal for example, transfer to audio frequency and video lead-out terminal (this partial circuit is not shown in Fig. 4) on the set-top box by its CVBS interface, to satisfy the reception requirement of rear end television set.
In described audio/video decoding chip U1, also be integrated with two groups of I2C bus interface, will be wherein one group of I2C bus interface by I2C bus F_SCL, F_SDA respectively with the corresponding connection with tuner T1 of described radiofrequency receiving chip RU1, realize on the one hand the selection of one group of tuned cell is wherein enabled, finish reception and down-converted requirement to the direct broadcasting satellite radiofrequency signal; Send control command to the tuned cell of enabling on the other hand, such as channel selecting signal etc., with response user's operation.Other one group of I2C bus interface of audio/video decoding chip U1 is connected communication via the audio frequency and video lead-out terminal on the set-top box with external television set by I2C bus D_SCL, D_SDA, carries out the information interaction between set-top box and the television set.
Provide by the rf gain control pin P_RFAGC output of audio/video decoding chip U1 for the required gain control signal RF_AGC of radiofrequency receiving chip RU1 and tuner T1.
The reference clock required for radiofrequency receiving chip RU1 work can be provided by the crystal oscillating circuit generation that crystal oscillator chip RY1 cooperates electric capacity RC23, RC24 to form; Then can share crystal oscillating circuit that crystal oscillator chip Y2 cooperates capacitor C 143, C144 to form for the required reference clock signal of tuner T1 and audio/video decoding chip U1 operation and export in the lump and provide, with the design of peripheral circuits.
Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and the variation that those skilled in the art make in essential scope of the present utility model, remodeling, interpolation or replacement also should belong to protection range of the present utility model.
Claims (10)
1. a direct broadcasting satellite digital TV set-top box is characterized in that: comprise tuned cell and the audio/video decoding chip that is built-in with the satellite-signal demodulator; Described tuned cell receives the direct broadcasting satellite radiofrequency signal, carry out converting baseband signal to after the down-converted, after transferring to decoding that described audio/video decoding chip carries out modulation demodulation and audio-video signal and processing, restore audio signal and the video signal transmission audio frequency and video lead-out terminal to the set-top box.
2. direct broadcasting satellite digital TV set-top box according to claim 1, it is characterized in that: in described tuned cell, be provided with satellite earth antenna and radiofrequency receiving chip, described satellite earth antenna receives the direct broadcasting satellite radiofrequency signal, and converting single core radio signal transmission to after described radiofrequency receiving chip carries out down-converted, the output base band signal transmission is to described audio/video decoding chip.
3. direct broadcasting satellite digital TV set-top box according to claim 2 is characterized in that: single core radiofrequency signal that described radiofrequency receiving chip will receive converts the base band signal transmission of a pair of quadrature in phase to described audio/video decoding chip.
4. direct broadcasting satellite digital TV set-top box according to claim 3 is characterized in that: described audio/video decoding chip connects the bus terminal of radiofrequency receiving chip, transmission control command by the I2C bus; The gain control end that connects radiofrequency receiving chip by rf gain control pin is sub, the transmission gain control signal.
5. direct broadcasting satellite digital TV set-top box according to claim 1, it is characterized in that: in described tuned cell, be provided with tuner, the rf inputs of described tuner receives the direct broadcasting satellite radiofrequency signal, after down-converted, convert the baseband signal of a pair of quadrature in phase to, transfer to described audio/video decoding chip.
6. direct broadcasting satellite digital TV set-top box according to claim 5 is characterized in that: described audio/video decoding chip connects the bus terminal of tuner, transmission control command by the I2C bus; The gain control end that connects radiofrequency receiving chip by rf gain control pin is sub, the transmission gain control signal.
7. direct broadcasting satellite digital TV set-top box according to claim 1, it is characterized in that: the pcb board in set-top box is provided with two groups of tuned cells, be provided with satellite earth antenna and radiofrequency receiving chip in one group of tuned cell therein, in other one group of tuned cell, be provided with tuner; Described audio/video decoding chip is connected corresponding connections of bus terminal with described radiofrequency receiving chip respectively by the I2C bus with tuner, selection is enabled wherein one group of tuned cell reception direct broadcasting satellite radiofrequency signal and carried out down-converted.
8. direct broadcasting satellite digital TV set-top box according to claim 7 is characterized in that: described audio/video decoding chip transfers to respectively gain control end of radiofrequency receiving chip and tuner by its rf gain control pin outputing gain control signal.
9. direct broadcasting satellite digital TV set-top box according to claim 7, it is characterized in that: in described set-top box, be provided with two groups of crystal oscillating circuits, one group of crystal oscillating circuit connects described radiofrequency receiving chip, another the group crystal oscillating circuit respectively with the corresponding connection with the audio/video decoding chip of described tuner.
10. each described direct broadcasting satellite digital TV set-top box in 9 according to claim 1, it is characterized in that: audio signal and vision signal after described audio/video decoding chip reduces by its CVBS interface output transfer to the audio frequency and video lead-out terminal on the set-top box.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220639379 CN202918450U (en) | 2012-11-28 | 2012-11-28 | Direct broadcasting satellite digital television set top box |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220639379 CN202918450U (en) | 2012-11-28 | 2012-11-28 | Direct broadcasting satellite digital television set top box |
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| Publication Number | Publication Date |
|---|---|
| CN202918450U true CN202918450U (en) | 2013-05-01 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220639379 Expired - Fee Related CN202918450U (en) | 2012-11-28 | 2012-11-28 | Direct broadcasting satellite digital television set top box |
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| CN (1) | CN202918450U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105611333A (en) * | 2015-12-28 | 2016-05-25 | 北京中传数广技术有限公司 | Satellite live broadcast system and method in support of longitude and latitude authorization |
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2012
- 2012-11-28 CN CN 201220639379 patent/CN202918450U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105611333A (en) * | 2015-12-28 | 2016-05-25 | 北京中传数广技术有限公司 | Satellite live broadcast system and method in support of longitude and latitude authorization |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| 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: 20130501 Termination date: 20191128 |