CN1455593A - Low error rate digital MUDS multi-path decimetric wave near-frequency wireless television transmitting system - Google Patents
Low error rate digital MUDS multi-path decimetric wave near-frequency wireless television transmitting system Download PDFInfo
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Abstract
The system work frequency is 400-800 MHz decimeter wave TV band. It comprises the basic station system, the relay station system and the user system. The basic station system comprises the broadband basic station, the adjacent frequency multi-operation synthesizer basic station, the fiber basic station, the bi-directional multimedia basic station and the multi-definition basic station. The relay system comprises the direct relay station and the transfer relay station. The user system comprises antenna, the digital top box and the digital TV receiver. It can transmit multi-channel digital TV program with wireless mode, eliminate the dynamic fake random disturb, has multiple digital signal secret key encryption.
Description
Technical field
The invention belongs to a kind of multi-channel television transmission system, particularly a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system.
Technical background
Existing multi-channel television transmission system has: CATV transmission system, MMDS multichannel microwave television transmission system (MMDS) etc.Wherein the cable TV neighbour to keep pouring in communication system transmission way many, laser propagation effect is good, shortcoming is to need wiring, cost height, big, the anti-Nature and Man of installation workload are that damage capability is poor, the operation maintenance workload is big, the incompatible multi-channel television covering problem that solves city suburbs and the such scattered settlement resident in rural area.MMDS multichannel microwave television system adopts wireless coverage, is fit to the scattered settlement region, and shortcoming is to have upper and lower converter noise, influences the rating quality, under the condition of television digitization, influences even more serious; Relative bandwidth is little in addition, and adjacent isolation is not high frequently, and wavelength is short, tree declines, rain declines, and problem is serious; MMDS multichannel microwave television transmission system can not realize that high-quality covers.
Technology contents
The object of the present invention is to provide a kind of low cost, high-quality multi-path adjacent frequency wireless digital TV transmission system, it transmits multichannel high-quality digital program with wireless mode, digital television signal is adopted dynamic pseudo-random descrambling and multiple key encryption and decryption, realize toll administration, the modern multi-channel television in city suburbs and rural area covers and multimedia covers in order to solve, practicable economical and practical means are provided, also can provide the mobile type digital television transmission.
Technical scheme of the present invention is: operating frequency is a 400-800MHZ decimever television frequency range; Total system is made up of base sub-system, relaying subsystem, user side subsystem three parts; Base sub-system comprises broadband type base station, adjacent multiplex's synthesis type frequently base station, optical-fiber type base station, two-way multimedia base station, multiple definition base station; Relay system comprises directly puts relay station and forward relay station; User side is made up of user antenna, top box of digital machine, digital television receiver etc.
Described directly put relay station be divided into unidirectional directly put relay station and two-wayly directly put relay station, described forward relay station is divided into unidirectional forward relay station and the two-way relay station of directly putting;
Each channel of described broadband type base station is made up of MPEG-2 code stream machine, the compatible group of single channel multichannel multiplexing machine, user management authoring system, CA scrambling machine, digital intermediate frequency modulator, Digital Up Convert channel plate, the adjacent frequency domain channel blender of digital decimeter wave, high linear digital MUDS wideband transmitter, broadband bipolar plate transmitting antenna.
Described digital intermediate frequency modulator is QAM intermediate frequency modulator or COFDM intermediate frequency modulator;
The TS by Moving Picture Experts Group-2 of described MPEG-2 code stream machine output single programs or Polymera flows to the compatible group of single channel multichannel multiplexing machine;
The mode of the compatible group of described single channel multichannel multiplexing machine by the time-division is multiplexed into the TS stream in a broadband with the TS stream of the TS stream of a plurality of single programs or a plurality of programs, and the program capacity of broadband TS stream is generally definition (720 * 576 * 25) TV programme in 6 covers;
Described user management and authoring system are to user's toll administration and to user's watching authorization; Its management information and broadband TS stream input to CA scrambling machine together;
Described CA scrambling machine adopts the dynamic scrambling of control word pseudorandom, and control word is encrypted, and forms keys such as EMC, EMM, multiplexingly transfers to the digital intermediate frequency modulator in TS stream; The digital medium-frequency signal that comes out from the digital intermediate frequency modulator joins Digital Up Convert channel plate; The Digital Up Convert channel plate of each channel inputs to the adjacent frequency domain channel blender of digital decimeter wave respectively and carries out neighbour's mixing frequently, and its mixed signal is amplified through high linear digital MUDS wideband transmitter, goes out by broadband bipolar plate transmission antennas transmit;
Described Digital Up Convert plate is made up of the first intermediate frequency low noise amplifying unit, the second intermediate frequency low noise amplifying unit, intermediate frequency sound table filter unit, two balanced mixings unit, high frequency low noise amplifying unit, the first minor spiral cavity filter unit, the second minor spiral cavity filter unit, adjustable damping unit, high linear amplification unit, accurate high stability crystal oscillator, crystal oscillator frequency divider, phase demodulation comparator, pre-divider, frequency divider and medium vibration VCO; By frequency accuracy and stability is 10
-7-10
-9Accurate high stability crystal oscillator source for referencial use, enter the phase demodulation comparator by the crystal oscillator frequency divider, the oscillator signal that medium vibration VCO produces enters the phase demodulation comparator by pre-divider and frequency divider, the phase demodulation comparator compares two paths of signals, mode with phase-locked loop, the frequency of oscillation of FEEDBACK CONTROL VCO changes the local oscillation signal f that frequency dividing ratio obtains different frequency
0Digital medium-frequency signal DIF is input to the first low noise intermediate frequency amplifier circuit amplifying unit, by the filtering of IF sound table, the second low noise intermediate frequency amplifying unit, through two balanced mixing unit and local oscillator f
0Carrying out two balance low noise mixing formation frequencies is f
0The high-frequency signal of ± DIF, carry out channel filtering by the first minor spiral cavity body filter, by high frequency low noise amplifying unit, adjustable attenuator conditioning signal intensity, import the second minor spiral cavity body filter again and carry out cavity filtering successively, through high linear amplification unit output;
Described high linear digital MUDS transmitter comprises a power amplifier, this power amplifier adopts negative preceding feedback power amplification, predistortion power amplification and three schemes of high-power rollback to improve the linearity, wherein high-power rollback type power amplifier is by low noise amplifying unit, 3dB broadband pottery coupler and 50 Ω build-out resistors, the modular of two performance unanimities promotes high linear amplification unit, the high linear power amplifying unit of the final stage of two performance unanimities, the high-power ceramic coupler in 3dB broadband, high-power 50 Ω build-out resistors and standing wave detect isolator and form; Radiofrequency signal is input to the low noise amplifying unit, entering 3dB pottery coupler carries out symmetry and is shunted to two-way, each road is carried out modular respectively and is promoted high linear amplification unit, the high linear power amplifying unit amplification of final stage, closing the road by the high-power ceramic coupler in 3dB broadband increases power, detects isolator by standing wave and eliminates reflected wave output;
Each channel of the adjacent multiplex's synthesis type frequently of described single channel emission base station comprises MPEG-2 code stream machine, single channel and compatible along separate routes group's multiplexing machine, user management authoring system, CA scrambling machine, digital intermediate frequency modulator, Digital Up Convert channel plate, high linear digital MUDS transmitter, numeric type multichannel decimeter wave adjacent multiplex's synthesizer and broadband bipolar plate transmitting antenna frequently;
A plurality of telepoint base stations that described optical-fiber type base station comprises the home base stations that links to each other with HFC fiber-coaxial net, links to each other with HFC fiber-coaxial net by DVB demodulation modulating unit; Described home base stations and telepoint base station all can be broadband type base station or the adjacent multiplex's synthesis type frequently of single channel emission base station; Described DVB demodulation modulating unit comprises two kinds of demodulation modulating units of DVB-C, DVB-T, described DVB-C demodulation modulating unit comprises DVB-C code stream receiver and QAM modulator, this DVB-C code stream receiver receives the TS stream from the MPEG-2 of HFC fiber-coaxial net, the QAM modulator carries out the QAM modulation with this TS stream, and the signal after the modulation inputs to telepoint base station; Described DVB-T demodulation modulating unit comprises DVB-T code stream receiver and COFDM modulator, this DVB-T code stream receiver receives the TS stream from the MPEG-2 of HFC fiber-coaxial net, the COFDM modulator carries out the COFDM modulation with this TS stream, and the signal after the modulation inputs to telepoint base station;
Described two-way multimedia base station comprises a plurality of DVB digital television channels, a plurality of DVB data broadcasting passage, Digital Up Convert channel plate, high linear digital MUDS transmitter, the equipment with the networking of broadband INT net, numeric type multichannel decimeter wave adjacent frequency multiplex's synthesizer and broadband bipolar plate transmitting antenna; Described DVB digital television channel comprises DVB-C digital television channel and DVB-T digital television channel; Described DVB digital television channel comprises DVB-C data broadcasting passage and DVB-T data broadcasting passage; Each DVB digital television channel and each DVB data broadcasting passage input to the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave by Digital Up Convert channel plate, high linear digital MUDS transmitter respectively, and broadband bipolar plate transmitting antenna links to each other with the adjacent multiplex's synthesizer frequently of this numeric type multichannel decimeter wave; Described equipment with the networking of broadband INT net comprises DVB gateway, down going channel, data feedback channel, CA system, DVB modulator, high linear digital MUDS transmitter, CDMA demodulating unit, the up receiving element of CDMA and reception antenna, down going channel links to each other with broadband INT net by the DVB gateway with data feedback channel, realizes the conversion of IP packet and TS stream and CDMA packet; Described down going channel, CA system, DVB modulator, high linear digital MUDS transmitter are connected to the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave successively; Described reception antenna, the up receiving element of CDMA, CDMA demodulating unit are connected to data feedback channel successively;
Each passage of described multiple definition base station comprises a plurality of different definition MEPG-2 code stream machines that link to each other with the compatible group of single channel multichannel multiplexing machine, and CA system, digital intermediate frequency modulator, Digital Up Convert channel plate, the high linear digital MUDS transmitter of connecting successively with the compatible group of single channel multichannel multiplexing machine, the high linear digital MUDS transmitter of each passage all links to each other with the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave, and the adjacent signal of multiplex's synthesizer frequently of this numeric type multichannel decimeter wave exports broadband bipolar plate transmitting antenna to; Described each channel bit stream machine comprises 1 high definition MEPG-2 code stream machine and 2 middle definition MEPG-2 code stream machines or comprises 1 high definition MEPG-2 code stream machine and 4 middle low definition MEPG-2 code stream machines, perhaps 6 middle definition MEPG-2 code stream machines, perhaps 12 middle low definition MEPG-2 code stream machines;
Describedly unidirectionally directly put alms giver's parabolic antenna that relay station connects successively, one-level broadband cavity body filter, low noise amplifier, secondary chamber fluid filter, high linear broadband power amplifier, three grades of cavity body filters, retransmit directional antenna;
Described unidirectional forward relay station comprises successively alms giver's parabolic antenna, one-level cavity body filter, low noise amplifier, frequency converter, the secondary chamber fluid filter of series connection, high linear broadband power amplifier, three grades of cavity body filters, retransmits omnidirectional antenna;
The described two-way relay station of directly putting comprises and is connected in parallel on alms giver's duplexer and retransmits up link and down link between the duplexer, and the alms giver's parabolic antenna that links to each other with alms giver's duplexer, the repeating transmission directional antenna that links to each other with the repeating transmission duplexer; Described down link comprises descending low noise amplifier, descending cavity body filter, the high linear power amplifier of downstream broadband of series connection successively; Described up link comprises up low noise amplifier, up cavity body filter, the high linear power amplifier in up broadband of series connection successively;
The two-way forward relay of described broadband type numeral MUDS station comprises and is connected in parallel on alms giver's duplexer and retransmits up link and down link between the duplexer, and the alms giver's parabolic antenna that links to each other with alms giver's duplexer, the repeating transmission omnidirectional antenna that links to each other with the repeating transmission duplexer; Described down link comprises descending low noise amplifier, descending frequency converter, descending cavity body filter and the high linear power amplifier of downstream broadband of series connection successively; Described up link comprises up low noise amplifier, up frequency converter, the high linear power amplifier of up cavity body filter and up broadband of series connection successively;
Described user side subsystem is made up of user's reception antenna, user's dual-mode antenna, number receiving set up box, number television receiver, user's two-way multimedia terminal.
Description of drawings
Fig. 1 is a system principle diagram of the present invention;
Fig. 2 is a broadband type base station theory diagram;
Fig. 3 is a Digital Up Convert channel plate theory diagram;
Fig. 4 is the high linear power amplifier theory diagram of high-power rollback molded breadth band;
Fig. 5 is adjacent multiplex's synthesis type frequently base station theory diagram;
Fig. 6 is an optical-fiber type base station theory diagram;
Fig. 7 is a two-way multimedia base station theory diagram;
Fig. 8 is a multiple definition base station theory diagram;
Fig. 9 is the unidirectional relay station theory diagram of directly putting;
Figure 10 is a unidirectional forward relay station theory diagram;
The two-way relay station theory diagram of directly putting of Figure 11;
Figure 12 is a two-way forward relay station theory diagram;
Figure 13 is user's subsystem theory diagram.
Embodiment
As shown in the figure:
System works frequency of the present invention is a 400-800MHZ decimever television frequency range; Total system is made up of base sub-system, relaying subsystem, user side subsystem three parts; Base sub-system comprises broadband type base station, adjacent multiplex's synthesis type frequently base station, optical-fiber type base station, two-way multimedia base station, multiple definition base station; Relay system comprises directly puts relay station and forward relay station; User side is made up of user antenna, top box of digital machine, digital television receiver etc.
Described directly put relay station be divided into unidirectional directly put relay station and two-wayly directly put relay station, described forward relay station is divided into unidirectional forward relay station and the two-way relay station of directly putting;
Each channel of described broadband type base station is made up of MPEG-2 code stream machine, the compatible group of single channel multichannel multiplexing machine, user management authoring system, CA scrambling machine, digital intermediate frequency modulator, Digital Up Convert channel plate, the adjacent frequency domain channel blender of digital decimeter wave, high linear digital MUDS wideband transmitter, broadband bipolar plate transmitting antenna.
Described digital intermediate frequency modulator is QAM intermediate frequency modulator or COFDM intermediate frequency modulator;
The TS by Moving Picture Experts Group-2 of described MPEG-2 code stream machine output single programs or Polymera flows to the compatible group of single channel multichannel multiplexing machine;
The mode of the compatible group of described single channel multichannel multiplexing machine by the time-division is multiplexed into the TS stream in a broadband with the TS stream of the TS stream of a plurality of single programs or a plurality of programs, and the program capacity of broadband TS stream is generally definition (720 * 576 * 25) TV programme in 6 covers;
Described user management and authoring system are to user's toll administration and to user's watching authorization; Its management information and broadband TS stream input to CA scrambling machine together;
Described CA scrambling machine adopts the dynamic scrambling of control word pseudorandom, and control word is encrypted, and forms keys such as EMC, EMM, multiplexingly transfers to the digital intermediate frequency modulator in TS stream; The digital medium-frequency signal that comes out from the digital intermediate frequency modulator joins Digital Up Convert channel plate; The Digital Up Convert channel plate of each channel inputs to the adjacent frequency domain channel blender of digital decimeter wave respectively and carries out neighbour's mixing frequently, and its mixed signal is amplified through high linear digital MUDS wideband transmitter, goes out by broadband bipolar plate transmission antennas transmit;
Described QAM intermediate frequency modulator generally adopts the 64QAM modulation, and the QAM modulation belongs to the DVB-C standard, is convenient to unify set-top box or digital television receiver standard with wired network, and brings into play advantage cheaply.For city suburbs and vast rural area, mainly be covered as the master with vegetation, multipath disturbs very little.User's reception antenna of the present invention adopts little radar reflection surface antenna, can effectively eliminate multipath and disturb, and the present invention is by actual test the widely: city suburbs and rural area can adopt the DVB-C standard to carry out wireless coverage fully.
COFDM belongs to the DVB-T standard, can effectively eliminate multipath and disturb, and is fit to the environment that reception of Mobile Digital TV environment and urban architecture compact district multipath disturb.The present invention adopts DVB-C and DVB-T standard mixed transport, and purpose is extensively to adapt to multiple reception environment in economical and practical mode, and the present invention also can adopt the DVB-S transmission, but the DVB-S availability of frequency spectrum is low, so do not adopt.
Described Digital Up Convert channel plate mainly is that the digital intermediate frequency signal after QA, the COFDM modulation is upconverted to analog television channels.China's analog television channels is that the bandwidth after 8MHZ bandwidth, the 64QAM modulation is the 6.6-7.0Mb/s bandwidth, can in analog channel, transmit fully, Digital Up Convert channel plate is different from simulation up-conversion channel plate, it requires bit error rate very low with the modulation error rate, require to have very low phase noise, high linear low noise amplifies and very high inband flatness height for this reason.The Digital Up Convert plate is by the first intermediate frequency low noise amplifying unit, the second intermediate frequency low noise amplifying unit, intermediate frequency sound table filter unit, two balanced mixings unit, high frequency low noise amplifying unit, the first minor spiral cavity filter unit, the second minor spiral cavity filter unit, adjustable damping unit, high linear amplification unit, accurate high stability crystal oscillator, crystal oscillator frequency divider, phase demodulation comparator, pre-divider, frequency divider,, medium vibration VCO forms; By frequency accuracy and stability is the accurate high stability crystal oscillator source for referencial use of 10-7-10-9, enter the phase demodulation comparator by the crystal oscillator frequency divider, the oscillator signal that medium vibration VCO produces enters the phase demodulation comparator by pre-divider and frequency divider, the phase demodulation comparator compares two paths of signals, mode with phase-locked loop, the frequency of oscillation of FEEDBACK CONTROL VCO changes the local oscillation signal f0 that frequency dividing ratio obtains different frequency; Digital medium-frequency signal DIF is input to the first low noise intermediate frequency amplifier circuit amplifying unit, by the filtering of IF sound table, the second low noise intermediate frequency amplifying unit, it is the high-frequency signal of f0 ± DIF that two balanced mixing unit of warp and local oscillator f0 carry out two balance low noise mixing formation frequencies, carry out channel filtering by the first minor spiral cavity body filter, successively by high frequency low noise amplifying unit, adjustable attenuator conditioning signal intensity, import the second minor spiral cavity body filter again and carry out cavity filtering, through high linear amplification unit output; Pass through technique scheme, Digital Up Convert channel plate is when output level is 80-110dBuv, its bit error rate BER reaches 1 * 10-9, (the MER value is big more for modulation error rate MER 〉=32dB, represent that actual error code is more little), digital intermediate frequency signal after the modulation upconverts to analog television channels, and this digital up-conversion channel plate can be used for all kinds base station of back.
The adjacent frequency domain channel blender of numeral decimeter wave adopts adjacent isolation frequently to reach the above adjacent frequency domain channel blender of 30dB, to reduce the phase mutual interference.The signal of adjacent frequency domain channel blender output, enter the high linear MUDS wideband transmitter of numeral and carry out power amplification, for reducing the bit error rate and the modulation error rate, transmitter of the present invention will be accomplished noise factor≤5.0dB of amplifying, linearity height, radio frequency power output is big, when the linearity requires 6 carrier waves equidistantly for 8MHZ, its mutual cadre enrolled among workers disturbs≤-45dBC, radio frequency power output 〉=5W under this state.
Described high linear digital MUDS transmitter comprises a power amplifier, this power amplifier adopts negative preceding feedback power amplification, predistortion power amplification and three schemes of high-power rollback to improve the linearity, wherein high-power rollback type power amplifier is by low noise amplifying unit, 3dB broadband pottery coupler and 50 Ω build-out resistors, the modular of two performance unanimities promotes high linear amplification unit, the high linear power amplifying unit of the final stage of two performance unanimities, the high-power ceramic coupler in 3dB broadband, high-power 50 Ω build-out resistors and standing wave detect isolator and form; Radiofrequency signal is input to the low noise amplifying unit, entering 3dB pottery coupler carries out symmetry and is shunted to two-way, each road is carried out modular respectively and is promoted high linear amplification unit, the high linear power amplifying unit amplification of final stage, closing the road by the high-power ceramic coupler in 3dB broadband increases power, detects isolator by standing wave and eliminates reflected wave output; Because of amplifying unit has all carried out the high linear amplification of back-off, adopt broadband 3dB pottery coupler in addition.This power amplifier linearity height, noise factor is low, the work zone is wide.This power amplifier also adapts to and is used for following adjacent multiplex (MUX) synthesis type base station frequently and relay station as the power amplification core component.
Transmitter output is input to broadband bipolar plate transmitting antenna by low-loss feedback pipe coaxial cable with signal and launches.In order to guarantee the broadband, the bipolar plate oscillator is wanted corner cut, makes the electromagnetic wave of different wave length that 1/4 corresponding λ harmonic oscillator all be arranged, to reach the purpose of spread bandwidth.
Each channel of described adjacent multiplex's synthesis type frequently base station comprises MPEG-2 code stream machine, single channel and compatible along separate routes group's multiplexing machine, user management authoring system, CA scrambling machine, digital intermediate frequency modulator, Digital Up Convert channel plate, high linear digital MUDS transmitter, numeric type multichannel decimeter wave adjacent multiplex's synthesizer and broadband bipolar plate transmitting antenna frequently; High linear digital MUDS transmitter of each passage makes the transmitting power of each passage increase, and is beneficial to transmit farther distance.Noise factor≤the 5.0dB of high linear digital MUDS transmitter, during power output 〉=20W, in the 7MHZ bandwidth mutual cadre enrolled among workers disturb≤-45dBC, under this index, guarantee its bit error rate BER≤10-7, modulation error rate MER 〉=30dB, the essential structure of high linear digital MUDS transmitter is identical with the broadband type transmitter, its core component power amplifier adopts negative preceding feedback power to amplify, and three schemes of predistortion power amplification and high-power rollback power amplification improve the linearity, reduce the noise that amplifies.
A plurality of telepoint base stations that described optical-fiber type base station comprises the home base stations that links to each other with HFC fiber-coaxial net, links to each other with HFC fiber-coaxial net by DVB demodulation modulating unit; Described home base stations and telepoint base station all can be broadband type base station or adjacent multiplex's synthesis type frequently base station; Described DVB demodulation modulating unit comprises two kinds of demodulation modulating units of DVB-C, DVB-T, described DVB-C demodulation modulating unit comprises DVB-C code stream receiver and QAM modulator, this DVB-C code stream receiver receives the TS stream from the MPEG-2 of HFC fiber-coaxial net, the QAM modulator carries out the QAM modulation with this TS stream, and the signal after the modulation inputs to telepoint base station; Described DVB-T demodulation modulating unit comprises DVB-T code stream receiver and COFDM modulator, this DVB-T code stream receiver receives the TS stream from the MPEG-2 of HFC fiber-coaxial net, the COFDM modulator carries out the COFDM modulation with this TS stream, and the signal after the modulation inputs to telepoint base station; Why the present invention will carry out this processing, is to utilize the error code correction function of DVB code stream receiver to reduce the error rate in the transmission.Telepoint base station can be the adjacent multiplex's synthesis type frequently of single channel base station, also can be wide bandwidth base station.
Described two-way multimedia base station comprises a plurality of DVB digital television channels, a plurality of DVB data broadcasting passage, Digital Up Convert channel plate, high linear digital MUDS transmitter, the equipment with the networking of broadband INT net, numeric type multichannel decimeter wave adjacent frequency multiplex's synthesizer and broadband bipolar plate transmitting antenna; Described DVB digital television channel comprises DVB-C digital television channel and DVB-T digital television channel; Described DVB data broadcasting passage comprises DVB-C data broadcasting passage and DVB-T data broadcasting passage; Each DVB digital television channel and each DVB data broadcasting passage input to the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave by Digital Up Convert channel plate, high linear digital MUDS transmitter respectively, and broadband bipolar plate transmitting antenna links to each other with the adjacent multiplex's synthesizer frequently of this numeric type multichannel decimeter wave; Described equipment with the networking of broadband INT net comprises DVB gateway, down going channel, data feedback channel, CA system, DVB modulator, high linear digital MUDS transmitter, CDMA demodulating unit, the up receiving element of CDMA and reception antenna, down going channel links to each other with broadband INT net by the DVB gateway with data feedback channel, realizes the conversion of IP packet and TS stream and CDMA packet; Described down going channel, CA system, DVB modulator, high linear digital MUDS transmitter are connected to the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave successively; Described reception antenna, the up receiving element of CDMA, CDMA demodulating unit are connected to data feedback channel successively;
Each passage of described multiple definition base station comprises a plurality of different definition MEPG-2 code stream machines that link to each other with the compatible group of single channel multichannel multiplexing machine, and CA system, digital intermediate frequency modulator, Digital Up Convert channel plate, the high linear digital MUDS transmitter of connecting successively with the compatible group of single channel multichannel multiplexing machine, the high linear digital MUDS transmitter of each passage all links to each other with the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave, and the adjacent signal of multiplex's synthesizer frequently of this numeric type multichannel decimeter wave exports broadband bipolar plate transmitting antenna to; Described each channel bit stream machine comprises 1 high definition MEPG-2 code stream machine and 2 middle definition MEPG-2 code stream machines or comprises 1 high definition MEPG-2 code stream machine and 4 middle low definition MEPG-2 code stream machines, perhaps 6 middle definition MEPG-2 code stream machines, perhaps 12 middle low definition MEPG-2 code stream machines;
The resolution of high definition TV is 1440 * 1080 * 25, middle definition was 720 * 576 * 25 (being equivalent to the DVD level), middle low definition was 352 * 576 * 25 (being equivalent to the SVCD level), the shared bandwidth of definition television was suitable during the shared bandwidth of one cover high definition TV was overlapped with 4, the shared bandwidth of low-definition television was suitable during the shared bandwidth of definition television was overlapped with 2 in one cover, in order to maximally utilise bandwidth resources and to satisfy the user's request of different levels, the present invention adopts the compatible mixed transport of multiple definition, by the bandwidth calculation that takies an analog channel, can transmit a cover high definition in the analog television channels bandwidth, definition digital television program in two covers; Can transmit low definition digital television program in a cover high definition, 4 covers; Can transmit definition digital television program in 6 covers; Can transmit low definition digital television program in definition in 2 covers, 8 covers; Can transmit low definition digital television program in 12 covers, transmission channel can adopt the DVB-C passage of QAM modulation, the DVB-T passage of COFDM modulation, the perhaps hybrid channel of the two.
Digital Transmission of the present invention still can realize normal reception when received field strength is 30dBuv, twilight-zone at the artificial antenna TV still can receive, covering efficient increases substantially, coverage distance also enlarges significantly simultaneously, but there is the blind area inevitably in radiovision, the present invention is like this equally, adopts relay system cleaning blind area for this reason.
Describedly unidirectionally directly put alms giver's parabolic antenna that relay station connects successively, one-level broadband cavity body filter, low noise amplifier, secondary chamber fluid filter, high linear broadband power amplifier, three grades of cavity body filters, retransmit directional antenna;
Alms giver's parabolic antenna receives aerial digital television signal and carries out broadband cavity filtering, and low noise amplifies, and cavity filtering is again carried out power amplification by high linear broadband power amplifier, and cavity filtering transfers out by retransmitting directional antenna., the same frequency feedback cycle between the transmitting-receiving be cut off here, receive-transmit isolation must be improved.The present invention compares before and after increasing dual-mode antenna, widen the distance of dual-mode antenna in the vertical and horizontal direction, dual-mode antenna adopts the technological means such as antenna of different polarization, increase receive-transmit isolation, general isolation between transmitting and receiving antenna is greater than this repeater gain 15dBC, adopting the repeater scheme, mainly is in order to save frequency resource.
Described unidirectional forward relay station comprises successively alms giver's parabolic antenna, one-level cavity body filter, low noise amplifier, frequency converter, the secondary chamber fluid filter of series connection, high linear broadband power amplifier, three grades of cavity body filters, retransmits omnidirectional antenna;
Different frequency is adopted in the transmitting-receiving of forward relay station, can effectively solve the problem that influences each other between the transmitting-receiving, will carry out frequency-conversion processing for this reason.This frequency converter adopts accurate high stability crystal oscillator, medium vibration VCO frequency synthesis, two balance or 4 balanced mixing technology, low noise sound pitch linear amplification, reach with the bit error rate that guarantees system and the modulation error rate that minimum (modulation error rate MER value is high more, the expression error rate is low more), when adopting Direct Conversion, for the multiple harmonic signal that prevents that local oscillator from producing, the use that will the filtering of employing sound table matches with LC filtering, the filtering of sound table obtains filter effect preferably, LC filtering filtering multiple frequence signal.
Numeral MUDS relay station is different from mobile communication and directly puts relay station, mainly is the broadband relaying, and each part of this relay station all will adopt broadband technology.
The described two-way relay station of directly putting comprises and is connected in parallel on alms giver's duplexer and retransmits up link and down link between the duplexer, and the alms giver's parabolic antenna that links to each other with alms giver's duplexer, the repeating transmission directional antenna that links to each other with the repeating transmission duplexer; Described down link comprises descending low noise amplifier, descending cavity body filter, the high linear power amplifier of downstream broadband of series connection successively; Described up link comprises up low noise amplifier, up cavity body filter, the high linear power amplifier in up broadband of series connection successively;
Adopt the method can enlarge the uplink and downlink coverage and the cleaning blind area of bi-directional digital MUDS multimedia base station, receive the downstream signal that the base station is come by donor antenna, be with outer filtering to change down link over to by duplexer, amplify through low noise amplifier, cavity body filter carries out filtering, the high linear power amplifier in broadband amplifies, and changes the repeating transmission omni-directional antenna transmission over to by duplexer filtering and goes out.The operation principle of up link needs to improve the isolation of transmitting-receiving here equally to descending similar, and its technical measures are suitable with unidirectional repeater; The insulated degree requirement of uplink and downlink reaches more than the 80dB, could effectively eliminate the mutual interference of uplink and downlink phase.Wideband digital MUDS of the present invention is two-way, and to put relay station uplink and downlink bandwidth in directly putting unequal, general descending broad and up narrower.
The two-way forward relay of described broadband type numeral MUDS station comprises and is connected in parallel on alms giver's duplexer and retransmits up link and down link between the duplexer, and the alms giver's parabolic antenna that links to each other with alms giver's duplexer, the repeating transmission omnidirectional antenna that links to each other with the repeating transmission duplexer; Described down link comprises descending low noise amplifier, descending frequency converter, descending cavity body filter and the high linear power amplifier of downstream broadband of series connection successively; Described up link comprises up low noise amplifier, up frequency converter, the high linear power amplifier of up cavity body filter and up broadband of series connection successively; Uplink and downlink all need carry out frequency-conversion processing, there is not the transmitting-receiving isolating problem in this two-way forward relay station, retransmitting antenna adopts omnidirectional antenna, up-downgoing is carried out duplexer by duplexer, the receive-transmit isolation of uplink and downlink requires to reach more than the 80dB, eliminate the phase mutual interference of up-downgoing, wideband power amplifer adopts high linear low noise, high flat degree power amplifier.
Described user side subsystem is made up of user's reception antenna, user's dual-mode antenna, number receiving set up box, number television receiver, user's two-way multimedia terminal.When wherein the user side antenna is used to receive merely, can adopt the low noise Active Receiving Antenna.Low noise Active Receiving Antenna of the present invention has two types of perpendicular polarization and horizontal polarizations, Active Receiving Antenna adopts ABS plastic injection molded, divide cover plate up and down, have the waterproof characteristics, adopt bipolar plate to make oscillator, amplify as the first order with low noise sound field pipe, and adopt inductance coil lightning protection and antistatic.
Claims (12)
1, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system is characterized in that it is made up of base sub-system, relaying subsystem, user side subsystem three parts; Described base sub-system comprises broadband type base station, adjacent multiplex's synthesis type frequently base station, optical-fiber type base station, two-way multimedia base station, multiple definition base station; Described relay system comprises directly puts relay station and forward relay station; Described user side is made up of user antenna, top box of digital machine, digital television receiver etc.;
Described directly put relay station be divided into unidirectional directly put relay station and two-wayly directly put relay station, described forward relay station is divided into unidirectional forward relay station and the two-way relay station of directly putting.
2, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1 is characterized in that each channel of described broadband type base station is made up of MPEG-2 code stream machine, the compatible group of single channel multichannel multiplexing machine, user management authoring system, CA scrambling machine, digital intermediate frequency modulator, Digital Up Convert channel plate, the adjacent frequency domain channel blender of digital decimeter wave, high linear digital MUDS wideband transmitter, broadband bipolar plate transmitting antenna;
Described digital intermediate frequency modulator is QAM intermediate frequency modulator or COFDM intermediate frequency modulator;
The TS by Moving Picture Experts Group-2 of described MPEG-2 code stream machine output single programs or Polymera flows to the compatible group of single channel multichannel multiplexing machine;
The mode of the compatible group of described single channel multichannel multiplexing machine by the time-division is multiplexed into the TS stream in a broadband with the TS stream of the TS stream of a plurality of single programs or a plurality of programs, and the program capacity of broadband TS stream is generally definition (720 * 576 * 25) TV programme in 6 covers;
Described user management and authoring system are to user's toll administration and to user's watching authorization; Its management information and broadband TS stream input to CA scrambling machine together;
Described CA scrambling machine adopts the dynamic scrambling of control word pseudorandom, and control word is encrypted, and forms keys such as EMC, EMM, multiplexingly transfers to the digital intermediate frequency modulator in TS stream; The digital medium-frequency signal that comes out from the digital intermediate frequency modulator joins Digital Up Convert channel plate; The Digital Up Convert channel plate of each channel inputs to the adjacent frequency domain channel blender of digital decimeter wave respectively and carries out neighbour's mixing frequently, and its mixed signal is amplified through high linear digital MUDS wideband transmitter, goes out by broadband bipolar plate transmission antennas transmit;
Described Digital Up Convert plate is made up of the first intermediate frequency low noise amplifying unit, the second intermediate frequency low noise amplifying unit, intermediate frequency sound table filter unit, two balanced mixings unit, high frequency low noise amplifying unit, the first minor spiral cavity filter unit, the second minor spiral cavity filter unit, adjustable damping unit, high linear amplification unit, accurate high stability crystal oscillator, crystal oscillator frequency divider, phase demodulation comparator, pre-divider, frequency divider and medium vibration VCO; By frequency accuracy and stability is 10
-7-10
-9Accurate high stability crystal oscillator source for referencial use, enter the phase demodulation comparator by the crystal oscillator frequency divider, the oscillator signal that medium vibration VCO produces enters the phase demodulation comparator by pre-divider and frequency divider, the phase demodulation comparator compares two paths of signals, mode with phase-locked loop, the frequency of oscillation of FEEDBACK CONTROL VCO changes the local oscillation signal f that frequency dividing ratio obtains different frequency
0Digital medium-frequency signal DIF is input to the first low noise intermediate frequency amplifier circuit amplifying unit, by the filtering of IF sound table, the second low noise intermediate frequency amplifying unit, through two balanced mixing unit and local oscillator f
0Carrying out two balance low noise mixing formation frequencies is f
0The high-frequency signal of ± DIF, carry out channel filtering by the first minor spiral cavity body filter, by high frequency low noise amplifying unit, adjustable attenuator conditioning signal intensity, import the second minor spiral cavity body filter again and carry out cavity filtering successively, through high linear amplification unit output.
3, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1 is characterized in that each channel of described adjacent multiplex's synthesis type frequently base station comprises MPEG-2 code stream machine, single channel and compatible along separate routes group's multiplexing machine, user management authoring system, CA scrambling machine, digital intermediate frequency modulator, Digital Up Convert channel plate, high linear digital MUDS transmitter, numeric type multichannel decimeter wave adjacent multiplex's synthesizer and broadband bipolar plate transmitting antenna frequently;
Described digital intermediate frequency modulator is QAM intermediate frequency modulator or COFDM intermediate frequency modulator;
The TS by Moving Picture Experts Group-2 of described MPEG-2 code stream machine output single programs or Polymera flows to the compatible group of single channel multichannel multiplexing machine;
The mode of the compatible group of described single channel multichannel multiplexing machine by the time-division is multiplexed into the TS stream in a broadband with the TS stream of the TS stream of a plurality of single programs or a plurality of programs, and the program capacity of broadband TS stream is generally definition (720 * 576 * 25) TV programme in 6 covers;
Described user management and authoring system are to user's toll administration and to user's watching authorization; Its management information and broadband TS stream input to CA scrambling machine together;
Described CA scrambling machine adopts the dynamic scrambling of control word pseudorandom, and control word is encrypted, and forms keys such as EMC, EMM, multiplexingly transfers to the digital intermediate frequency modulator in TS stream; The digital medium-frequency signal that comes out from the digital intermediate frequency modulator joins Digital Up Convert channel plate; The Digital Up Convert channel plate of each channel is imported paramount linear digital MUDS transmitter amplification respectively and close road output in the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave, goes out by broadband bipolar plate transmission antennas transmit;
Described Digital Up Convert plate is made up of the first intermediate frequency low noise amplifying unit, the second intermediate frequency low noise amplifying unit, intermediate frequency sound table filter unit, two balanced mixings unit, high frequency low noise amplifying unit, the first minor spiral cavity filter unit, the second minor spiral cavity filter unit, adjustable damping unit, high linear amplification unit, accurate high stability crystal oscillator, crystal oscillator frequency divider, phase demodulation comparator, pre-divider, frequency divider and medium vibration VCO; By frequency accuracy and stability is 10
-7-10
-9Accurate high stability crystal oscillator source for referencial use, enter the phase demodulation comparator by the crystal oscillator frequency divider, the oscillator signal that medium vibration VCO produces enters the phase demodulation comparator by pre-divider and frequency divider, the phase demodulation comparator compares two paths of signals, mode with phase-locked loop, the frequency of oscillation of FEEDBACK CONTROL VCO changes the local oscillation signal f that frequency dividing ratio obtains different frequency
0Digital medium-frequency signal DIF is input to the first low noise intermediate frequency amplifier circuit amplifying unit, by the filtering of IF sound table, the second low noise intermediate frequency amplifying unit, through two balanced mixing unit and local oscillator f
0Carrying out two balance low noise mixing formation frequencies is f
0The high-frequency signal of ± DIF, carry out channel filtering by the first minor spiral cavity body filter, by high frequency low noise amplifying unit, adjustable attenuator conditioning signal intensity, import the second minor spiral cavity body filter again and carry out cavity filtering successively, through high linear amplification unit output.
4, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claim 2 or 3, it is characterized in that described high linear digital MUDS transmitter comprises a power amplifier, this power amplifier adopts negative preceding feedback power to amplify, three schemes of predistortion power amplification and high-power rollback improve the linearity, wherein high-power rollback type power amplifier is by the low noise amplifying unit, 3dB broadband pottery coupler and 50 Ω build-out resistors, the modular of two performance unanimities promotes high linear amplification unit, the high linear power amplifying unit of the final stage of two performance unanimities, the high-power ceramic coupler in 3dB broadband, high-power 50 Ω build-out resistors and standing wave detect isolator and form; Radiofrequency signal is input to the low noise amplifying unit, entering 3dB pottery coupler carries out symmetry and is shunted to two-way, each road is carried out modular respectively and is promoted high linear amplification unit, the high linear power amplifying unit amplification of final stage, closing the road by the high-power ceramic coupler in 3dB broadband increases power, detects isolator by standing wave and eliminates reflected wave output.
5, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1 is characterized in that described optical-fiber type base station comprises the home base stations that links to each other with HFC fiber-coaxial net, passes through a plurality of telepoint base stations that DVB demodulation modulating unit links to each other with HFC fiber-coaxial net; Described home base stations and telepoint base station all can be broadband type base station or adjacent multiplex's synthesis type frequently base station; Described DVB demodulation modulating unit comprises two kinds of demodulation modulating units of DVB-C, DVB-T, described DVB-C demodulation modulating unit comprises DVB-C code stream receiver and QAM modulator, this DVB-C code stream receiver receives the TS stream from the MPEG-2 of HFC fiber-coaxial net, the QAM modulator carries out the QAM modulation with this TS stream, and the signal after the modulation inputs to telepoint base station; Described DVB-T demodulation modulating unit comprises DVB-T code stream receiver and COFDM modulator, this DVB-T code stream receiver receives the TS stream from the MPEG-2 of HFC fiber-coaxial net, the COFDM modulator carries out the COFDM modulation with this TS stream, and the signal after the modulation inputs to telepoint base station.
6, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1 is characterized in that described two-way multimedia base station comprises a plurality of DVB digital television channels, a plurality of DVB data broadcasting passage, Digital Up Convert channel plate, high linear digital MUDS transmitter, nets equipment, numeric type multichannel decimeter wave adjacent the multiplex's synthesizer and the broadband bipolar plate transmitting antenna frequently of networking with broadband INT; Described DVB digital television channel comprises DVB-C digital television channel and DVB-T digital television channel; Described DVB data broadcasting passage comprises DVB-C data broadcasting passage and DVB-T data broadcasting passage; Each DVB digital television channel and each DVB data broadcasting passage input to the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave by Digital Up Convert channel plate, high linear digital MUDS transmitter respectively, and broadband bipolar plate transmitting antenna links to each other with the adjacent multiplex's synthesizer frequently of this numeric type multichannel decimeter wave; Described equipment with the networking of broadband INT net comprises DVB gateway, down going channel, data feedback channel, CA system, DVB modulator, high linear digital MUDS transmitter, CDMA demodulating unit, the up receiving element of CDMA and reception antenna, down going channel links to each other with broadband INT net by the DVB gateway with data feedback channel, realizes the conversion of IP packet and TS stream and CDMA packet; Described down going channel, CA system, DVB modulator, high linear digital MUDS transmitter are connected to the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave successively; Described reception antenna, the up receiving element of CDMA, CDMA demodulating unit are connected to data feedback channel successively.
7, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1, each passage that it is characterized in that described multiple definition base station comprises a plurality of different definition MEPG-2 code stream machines that link to each other with the compatible group of single channel multichannel multiplexing machine, and the CA system of connecting successively with the compatible group of single channel multichannel multiplexing machine, the digital intermediate frequency modulator, Digital Up Convert channel plate, high linear digital MUDS transmitter, the high linear digital MUDS transmitter of each passage all links to each other with the adjacent multiplex's synthesizer frequently of numeric type multichannel decimeter wave, and the adjacent signal of multiplex's synthesizer frequently of this numeric type multichannel decimeter wave exports broadband bipolar plate transmitting antenna to; Described each channel bit stream machine comprises 1 high definition MEPG-2 code stream machine and 2 middle definition MEPG-2 code stream machines or comprises 1 high definition MEPG-2 code stream machine and 4 middle low definition MEPG-2 code stream machines, perhaps 6 middle definition MEPG-2 code stream machines, perhaps 12 middle low definition MEPG-2 code stream machines.
8, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1 is characterized in that describedly unidirectionally directly putting alms giver's parabolic antenna that relay station comprises series connection successively, one-level broadband cavity body filter, low noise amplifier, secondary chamber fluid filter, high linear broadband power amplifier, three grades of cavity body filters, retransmitting directional antenna; Described unidirectional forward relay station comprises successively alms giver's parabolic antenna, one-level cavity body filter, low noise amplifier, frequency converter, the secondary chamber fluid filter of series connection, high linear broadband power amplifier, three grades of cavity body filters, retransmits omnidirectional antenna.
9, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1, it is characterized in that the described two-way relay station of directly putting comprises and is connected in parallel on alms giver's duplexer and retransmits up link and down link between the duplexer, and the alms giver's parabolic antenna that links to each other with alms giver's duplexer, the repeating transmission directional antenna that links to each other with the repeating transmission duplexer; Described down link comprises descending low noise amplifier, descending cavity body filter, the high linear power amplifier of downstream broadband of series connection successively; Described up link comprises up low noise amplifier, up cavity body filter, the high linear power amplifier in up broadband of series connection successively;
10, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1 is characterized in that described unidirectional forward relay station comprises alms giver's parabolic antenna, one-level cavity body filter, low noise amplifier, frequency converter, the secondary chamber fluid filter of series connection successively, high linear broadband power amplifier, three grades of cavity body filters, retransmits omnidirectional antenna;
11, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1, it is characterized in that described two-way forward relay station comprises is connected in parallel on alms giver's duplexer and retransmits up link and down link between the duplexer, and the alms giver's parabolic antenna that links to each other with alms giver's duplexer, the repeating transmission omnidirectional antenna that links to each other with the repeating transmission duplexer; Described down link comprises descending low noise amplifier, descending frequency converter, descending cavity body filter and the high linear power amplifier of downstream broadband of series connection successively; Described up link comprises up low noise amplifier, up frequency converter, the high linear power amplifier of up cavity body filter and up broadband of series connection successively.
12, a kind of low error rate numeral MUDS multichannel decimeter wave adjacent frequency wireless television transmission system as claimed in claim 1 is characterized in that described user side subsystem is made up of user's reception antenna, user's dual-mode antenna, number receiving set up box, number television receiver, user's two-way multimedia terminal.
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| CN03118153A CN1455593A (en) | 2003-03-03 | 2003-03-03 | Low error rate digital MUDS multi-path decimetric wave near-frequency wireless television transmitting system |
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| CN03118153A CN1455593A (en) | 2003-03-03 | 2003-03-03 | Low error rate digital MUDS multi-path decimetric wave near-frequency wireless television transmitting system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104378650A (en) * | 2014-11-14 | 2015-02-25 | 青岛龙泰天翔通信科技有限公司 | Digital MUDS multi-channel decimetric adjacent-frequency radio television transmission system with low error rate |
| WO2016150031A1 (en) * | 2015-03-20 | 2016-09-29 | 京东方科技集团股份有限公司 | Video signal wireless transmitter, receiver, transmission system, and display system |
-
2003
- 2003-03-03 CN CN03118153A patent/CN1455593A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104378650A (en) * | 2014-11-14 | 2015-02-25 | 青岛龙泰天翔通信科技有限公司 | Digital MUDS multi-channel decimetric adjacent-frequency radio television transmission system with low error rate |
| WO2016150031A1 (en) * | 2015-03-20 | 2016-09-29 | 京东方科技集团股份有限公司 | Video signal wireless transmitter, receiver, transmission system, and display system |
| US10230926B2 (en) | 2015-03-20 | 2019-03-12 | Boe Technology Group Co., Ltd. | Wireless video signal transmitter, receiver, transmission system and display system |
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