CN201199715Y - Set-top box capable of wireless receiving digital wired network signal - Google Patents
Set-top box capable of wireless receiving digital wired network signal Download PDFInfo
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- CN201199715Y CN201199715Y CNU2008200473310U CN200820047331U CN201199715Y CN 201199715 Y CN201199715 Y CN 201199715Y CN U2008200473310 U CNU2008200473310 U CN U2008200473310U CN 200820047331 U CN200820047331 U CN 200820047331U CN 201199715 Y CN201199715 Y CN 201199715Y
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Abstract
The utility model discloses a set-top box for wirelessly receiving digital wired network signals, which comprises a radio-frequency head; an antenna and a receiving module which are used for receiving a wired network digital signal or a broadcast signal are connected with the signal input terminal of the radio-frequency head, wherein, the receiving module comprises an input matching circuit, an amplifying circuit and an output matching circuit which are connected in sequence, and the output matching circuit is connected with the input terminal of the radio-frequency head. In the set-top box, the digital and the analog television/broadcast signals which are transmitted by a cable television network are received by the wireless antenna, therefore, a connecting line with the cable television network is eliminated, the operation is more convenient, and the trouble of wiring of the cable televisions in families is solved; in addition, since the improvement is made to the input and output matching circuits and the amplifying circuit, the input and output matching circuits and the amplifying circuit can not interfere the normal work of other electric appliances during the work, and the wireless receiving thereof is not easy to be affected by the other electric appliances in normal work, therefore, the good receiving effect can be guaranteed and the anti-disturbing capability is strong.
Description
Technical field
The utility model relates to the digital television broadcasting field, be specifically related to a kind of can wireless receiving to the digital-to-analog TV signal of cable TV network transmission and the set-top box of broadcast singal.
Background technology
Along with the development of digital television techniques, digital signaling system is strong with its antijamming capability, be convenient to characteristics such as storage, processing and exchange, become the topmost transmission technology in the modern cable TV network.Digital television signal can solve all drawbacks of anolog TV signals, in the digital television signal transmission system, the analog signal that information source is sent becomes digital television signal through the source encoding of digital terminal, the digital signal that terminal is sent, become the digital television signal that is suitable for Channel Transmission through chnnel coding, by modulator signal is modulated on the cable TV network then.
Each country successively from initial anolog TV signals complete upgrading to adopting digital television signal to transmit, but now vast user is also using simulated television, change become can receiving digital signals digital television, compare Ben Taigao, can not one the step realize that occurred can receiving digital signals and can be exchanged into the set-top box that simulated television can receive in various countries at present.The different three major types that divides of mode of the digital modulation signals that set-top box also adopts because of various countries, European DVB-T, the ATSC of the U.S. and part other countries, standards such as Japanese ISDB-T.Tsing-Hua University of China and Shanghai Communications University are also at the standard DMB-H that researches and develops China.In a period of transition, China's cable digital TV standard and satellite television standard have adopted European standard DVB-C and DVB-S to realize that being upgraded to digital television signal from anolog TV signals is transferred to the user before this.
The top box of digital machine of existing cable TV is connected to all needs other connecting line on the cable TV network, and set-top box also needs connecting line to be connected with television set, Duo connecting line so, the trouble that causes the user to use.In addition, after connecting by connecting line, can only be according to the length of connecting line, the position of mobile set-top box and television set among a small circle, this is restricted for the user of the use location that will adjust television set.
The patent No. is that the patent documentation of CN200720118885.0 discloses a kind of wireless digital set-top box, it comprises antenna, digital tuner, AD modular converter, demodulation module, micro controller unit, decoder module, the numeral tuner is by described antenna receiving signal, received signal obtains transmission code stream after through tuning, analog-to-digital conversion, the demodulation of DMB-TH information source, is called by micro controller unit then and carries out video and audio frequency output after decoder module is handled.This wireless digital set-top box is used to receive aerial digital signal, solves remote districts, the problem of receiving digital television.
The utility model content
The technical problem that the utility model need solve provides the TV signal of digital-to-analog compatibility of a kind of wireless receiving cable TV network transmission and the set-top box of broadcast singal.
Designed a kind of set-top box of wireless receiving digital cable TV signal according to above-mentioned purpose, the ripe circuit that comprises tuner and other existing set-top box, as power amplifier module, modular converter, demodulation module, micro controller unit, decoder module, be connected with antenna and the receiver module that is used to receive cable network digital signal or broadcast singal at the signal input part of tuner.
As the utility model preferred version be: described receiver module comprises input matching circuit, amplifying circuit and the output matching circuit that order links, and this output matching circuit connects with the tuner input.
Described input matching circuit is made up of resistance R 2, coupling capacitance C3 and integrating circuit that order links, and the signal that antenna receives connects with input amplifier through resistance R 2, coupling capacitance C3, integrating circuit.
Described amplifying circuit comprises triode Q1, field effect transistor Q2, Q3 and biasing resistor R8, R9, R10, R11, R12, the base stage of triode Q1 connects with integrating circuit, the collector electrode of Q1 connects with the grid of field effect transistor Q2, the drain electrode of Q2 connects with the grid of field effect transistor Q3, and the drain electrode of Q3 connects with output matching circuit.
Integrating circuit and output coupling capacitor C17, coupling resistance R22 that described output matching circuit comprises resistance R 15, R16, capacitor C 11, is made up of resistance R 17～R20 and capacitor C 12～C15, capacitor C 11, through amplifying signal after resistance R 15, R16, capacitor C 11 handled, enter the four group inte gration processing of circuit that resistance R 17～R20 and capacitor C 12～C15 form, connect with the tuner input through coupling capacitance C17, coupling resistance R22.
As the improvement to such scheme be: the integrating circuit described in the input matching circuit comprises R3, R4, R5, R6, R7, capacitor C 4, C5, C6, C7, C8, resistance R 3, capacitor C 4 are formed 5 group inte gration circuit with resistance R 6, capacitor C 7 with resistance R 7, capacitor C 8 with resistance R 5, capacitor C 6 with resistance R 4, capacitor C 5, and resistance R 7 also connects with the input of amplifying circuit.The emitter of triode Q1 in the amplifying circuit also connects with resistance R 9, capacitor C 16; The source electrode of field effect transistor Q2 also connects with resistance R 13, capacitor C 9; The source electrode of field effect transistor Q3 also connects with resistance R 14, capacitor C 10.
The utility model can increase the efficient antenna plate on the back plate of set-top box on the basis of existing set-top box structure, this antenna plate is close to the back plate, and nothing is stretched out, and makes complete machine seem very harmonious, attractive in appearance.The utility model receives the numeral and the simulated television/broadcast singal of cable TV network transmission by antenna wireless, removed line from cable TV network, use conveniently, shift position that can be random has solved wiring worries within the family such as cable TV.In addition, the utility model improves input and output matching circuit and amplifying circuit, do not disturb the operate as normal of other electrical equipment in the middle of work, also be not easy to be disturbed its wireless receiving by the electrical equipment of other operate as normal, assurance receives well, antijamming capability is strong.
Description of drawings
Fig. 1 is the receiver module circuit theory diagrams in the set-top box of the utility model wireless receiving digital cable TV signal.
Embodiment
For the ease of those skilled in the art's understanding, the utility model structural principle is described in further detail below in conjunction with specific embodiment and accompanying drawing:
The utility model set-top box is except comprising tuner, also comprise ripe circuit such as power amplifier module, modular converter, demodulation module, micro controller unit, decoder module, inventive point of the present utility model is the wireless connections that realize set-top box and cable network, increased receiver module, therefore, only the specific implementation of receiver module is set forth below.
As shown in Figure 1, the receiver module circuit theory diagrams in the set-top box of the utility model wireless receiving digital cable TV signal.The cable network digital television signal that antenna ANTENNA receives connects with the signal input part of tuner through input matching circuit, amplifying circuit and output matching circuit.
Described input matching circuit is made up of resistance R 2, coupling capacitance C3 and integrating circuit that order links, and the signal that antenna receives connects with input amplifier through resistance R 2, coupling capacitance C3, integrating circuit.Described integrating circuit comprises R3, R4, R5, R6, R7, capacitor C 4, C5, C6, C7, C8, resistance R 3, capacitor C 4 are formed 5 group inte gration circuit with resistance R 6, capacitor C 7 with resistance R 7, capacitor C 8 with resistance R 5, capacitor C 6 with resistance R 4, capacitor C 5, and resistance R 7 also connects with the input of amplifying circuit.
Described amplifying circuit comprises triode Q1, field effect transistor Q2, Q3 and biasing resistor R8, R9, R10, R11, R12, the base stage of triode Q1 connects with integrating circuit, the collector electrode of Q1 connects with the grid of field effect transistor Q2, the drain electrode of Q2 connects with the grid of field effect transistor Q3, and the drain electrode of Q3 connects with output matching circuit (OUT1).The emitter of triode Q1 also connects with resistance R 9, capacitor C 16; The source electrode of field effect transistor Q2 also connects with resistance R 13, capacitor C 9; The source electrode of field effect transistor Q3 also connects with resistance R 14, capacitor C 10.
Integrating circuit and output coupling capacitor C17, coupling resistance R22 that described output matching circuit comprises resistance R 15, R16, capacitor C 11, is made up of resistance R 17～R20 and capacitor C 12～C15, capacitor C 11, through amplifying signal after resistance R 15, R16, capacitor C 11 handled, enter the four group inte gration processing of circuit that resistance R 17～R20 and capacitor C 12～C15 form, connect with tuner input (OUT TOTV) through coupling capacitance C17, coupling resistance R22.
Principle of the present utility model is: the signal according to Digital Television is to adopt qam mode, this modulation system is called the quadrature width of cloth modulates mutually, and it was both modulated the amplitude of carrier wave, again the phase place of carrier wave was modulated, again because amplitude modulation is balanced amplitude modulation, so suppressed carrier wave.Its energy is evenly distributed in the whole qualification bandwidth, and therefore, a digital TV channel does not only have so-called pix carrier, does not have sound carrier yet.If fidelity is not enough, will show as: reticulate pattern is arranged in the image, roll interference such as bar, signal to noise ratio shows as the wave point of making an uproar in the image inadequately.And digital signal is a discrete signal, weighs the standard of its quality and can only estimate with the correctness that the value (or state) of signal is judged.The index deterioration of digital signal shows as mosaic, quiet Frame to the image interruption, does not have the progressive formation of the sort of deterioration of analog signal.National standard is recommended, and in the network of numerical value and the compatible transmission of simulation, the level ratio analog channel level of digital channel should hang down 10db μ V.Its objective is the nonlinear distortion that reduces digital signal.In addition, by international standard, in order to guarantee good reception, before the RS error correction that enters the receiving demodulation device, error rate BER should be less than 10E-4.
The field intensity that is transported to each user's terminal in cable TV network all is the same, and the utility model is to be received in the faint radio wave that user terminal sends in effective 2 meters.Be that with traditional wireless receiving TV characteristics receiving ability strengthens 20-25DB.The metal-oxide-semiconductor that the utility model is selected for use is selecting can to make the signal of the more stable reception of the utility model set-top box from cable TV network on the working point with on the input and output coupling.By the tuner signal input part in set-top box be connected with one efficiently, antijamming capability is strong, receiving sensitivity is high antenna.This antenna places on the antenna plate, antenna plate is placed on the back plate of set-top box, and antenna plate is connected with the tuner signal input part of set-top box inside, and antenna plate is close to the back plate, and nothing is stretched out, and makes complete machine seem very harmonious, attractive in appearance.
Amplifying circuit in the digital television signal reflecting system is operated in 470MHz～860MHz, need realize impedance matching in broad frequency range.Amplifying circuit input and output and inter-stage all adopt reactance matching network to carry out multistage impedance conversion.This network only plays matching effect, and excess loss power can not guarantee maximum transmission coefficient, device property is played proportionality action, and can satisfy the needed bandwidth requirement of system.The utility model adopts brand-new input and output matching circuit, has the strong and strong characteristics of antijamming capability of receiving ability.
In amplifying circuit, small signal S-parameters can be used for the design of Class A amplifying circuit, just requires the amplification of signal to be limited in the transistorized range of linearity substantially.Because amplifier is operated in the inelastic region, so small-signal is approximate invalid usually, must try to achieve transistorized Large-Signal S-Parameter or impedance this moment, to obtain rational design effect.In general, Class A operating state distortion factor minimum has good linearty.So on receiver module circuit of the present utility model, adopted the design of Class A amplifying circuit, make digital television signal through still destroyed after amplifying, and the signal that receives in set-top box will be more stable, reached and had the effect of connecting line.
Compared with prior art, the utility model has adopted brand-new input and output by simple circuit Match circuit flows to STB to faint signal amplification thereby reach, and has realized wireless connections. The utility model can be stablized the DTV/broadcast singal that receives the household wired TV network transmission, makes Connect cable TV network and seem simpler more convenient.
The utility model STB can receive the Digital and analog TV/broadcast singal in the cable network, For the TV signal of the Digital and analog compatibility that makes reception adopts the LDMOS FET of Motorola device MRF373 is as the amplification chip of power amplifier. This chip on linear, gain and fan-out capability with respect to BJT Device has bigger lifting, and the reliability and maintainability of emitter is improved greatly.
Compare with the ambipolar power tube of traditional decimetric wave, LDMOS FET has following remarkable advantage:
1, can in high standing-wave ratio (VSWR=10:1) situation, work;
2, gain high (representative value 13dB);
3, saturation curve is level and smooth, is conducive to analog-and digital-TV RF signals and amplifies;
4, can bear the big power of overdriving, be specially adapted to the overloading of COFDM modulation among the DVB-T The ripple signal;
5, biasing circuit is simple, need not the active Low ESR biasing circuit of the complicated positive temperature-compensating of band.
Claims (7)
1. the set-top box of a wireless receiving digital cable network signal comprises tuner, it is characterized in that: the signal input part at tuner is connected with antenna and the receiver module that is used to receive cable network digital signal or broadcast singal.
2. the set-top box of wireless receiving digital cable network signal according to claim 1, it is characterized in that: described receiver module comprises input matching circuit, amplifying circuit and the output matching circuit that order links, and this output matching circuit connects with the tuner input.
3. the set-top box of wireless receiving digital cable network signal according to claim 2, it is characterized in that: described input matching circuit is made up of resistance R 2, coupling capacitance C3 and integrating circuit that order links, and the signal that antenna receives connects with input amplifier through resistance R 2, coupling capacitance C3, integrating circuit.
4. the set-top box of wireless receiving digital cable network signal according to claim 3, it is characterized in that: described integrating circuit comprises R3, R4, R5, R6, R7, capacitor C 4, C5, C6, C7, C8, resistance R 3, capacitor C 4 are formed 5 group inte gration circuit with resistance R 6, capacitor C 7 with resistance R 7, capacitor C 8 with resistance R 5, capacitor C 6 with resistance R 4, capacitor C 5, and resistance R 7 also connects with the input of amplifying circuit.
5. according to the set-top box of claim 2 or 3 described wireless receiving digital cable network signals, it is characterized in that: described amplifying circuit comprises triode Q1, field effect transistor Q2, Q3 and biasing resistor R8, R9, R10, R11, R12, the base stage of triode Q1 connects with integrating circuit, the collector electrode of Q1 connects with the grid of field effect transistor Q2, the drain electrode of Q2 connects with the grid of field effect transistor Q3, and the drain electrode of Q3 connects with output matching circuit.
6. the set-top box of wireless receiving digital cable network signal according to claim 5 is characterized in that: the emitter of triode Q1 also connects with resistance R 9, capacitor C 16; The source electrode of field effect transistor Q2 also connects with resistance R 13, capacitor C 9; The source electrode of field effect transistor Q3 also connects with resistance R 14, capacitor C 10.
7. the set-top box of wireless receiving digital cable network signal according to claim 6, it is characterized in that: integrating circuit and output coupling capacitor C17, coupling resistance R22 that described output matching circuit comprises resistance R 15, R16, capacitor C 11, is made up of resistance R 17～R20 and capacitor C 12～C15, capacitor C 11, through amplifying signal after resistance R 15, R16, capacitor C 11 handled, enter the four group inte gration processing of circuit that resistance R 17～R20 and capacitor C 12～C15 form, connect with the tuner input through coupling capacitance C17, coupling resistance R22.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008200473310U CN201199715Y (en) | 2008-05-01 | 2008-05-01 | Set-top box capable of wireless receiving digital wired network signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008200473310U CN201199715Y (en) | 2008-05-01 | 2008-05-01 | Set-top box capable of wireless receiving digital wired network signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201199715Y true CN201199715Y (en) | 2009-02-25 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008200473310U Expired - Fee Related CN201199715Y (en) | 2008-05-01 | 2008-05-01 | Set-top box capable of wireless receiving digital wired network signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201199715Y (en) |
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2008
- 2008-05-01 CN CNU2008200473310U patent/CN201199715Y/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090225 Termination date: 20140501 |