CN109547037A - A kind of DMB emission system that can emit III wave band and L-band simultaneously - Google Patents
A kind of DMB emission system that can emit III wave band and L-band simultaneously Download PDFInfo
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- CN109547037A CN109547037A CN201811615635.7A CN201811615635A CN109547037A CN 109547037 A CN109547037 A CN 109547037A CN 201811615635 A CN201811615635 A CN 201811615635A CN 109547037 A CN109547037 A CN 109547037A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/005—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/02—Transmitters
- H04B1/04—Circuits
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/02—Transmitters
- H04B1/04—Circuits
- H04B2001/0491—Circuits with frequency synthesizers, frequency converters or modulators
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
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Abstract
The present invention relates to a kind of DMB emission systems that can emit III wave band and L-band simultaneously, belong to wireless communication field.The system includes: COFDM encoder, upconverter, power splitter, III band filter, L-band frequency-variable module, power amplifier and transmitting antenna；L-band frequency-variable module includes low-noise amplifier, phase-locked loop frequency source part, Direct conversion module and L-band bandpass filter；Phase-locked loop frequency source part includes constant-temperature crystal oscillator and PLL.In L-band frequency-variable module, after III band signal first passes through low-noise amplifier amplification, Direct conversion part is accessed, while local oscillation signal is accessed into Direct conversion part, III band signal and local oscillation signal are partially completed mixing in Direct conversion；Mixed frequency signal access L-band bandpass filter is filtered.The present invention solves the signal covering problem in practical application, promotes the user experience of DMB product, reduces cost, simplifies structure.
Description
Technical field
The invention belongs to wireless communication fields, are related to a kind of DMB emission system that can emit III wave band and L-band simultaneously.
Background technique
Digital multimedia broadcasting (Digital Multimedia Broadcasting, DMB) is from digital audio broadcasting
On the basis of develop, be a kind of wireless high-speed information transmission technology, it is sufficiently used digital audio broadcasting
(Digital Audio Broadcasting, DAB), DAB will functionally transmit single audio-frequency information and be extended to data, text
The variety carriers such as word, figure and video.
In the practical application of digital multimedia broadcasting, by the wireless receiver structure of emission system and all kinds of multimedia terminals
At.
Existing DMB emission system can only launch single wave band (III wave band or L-band), in actual application,
DMB system is normally applied III wave band (174MHz-250MHz).But in the more application scenarios of certain barriers, III wave
The signal covering of segment signal is not angle that is very good, taking the power for increasing DMB emission system transmitting signal or adjust antenna
The problem of not can solve signal covering declines so as to cause the user experience of DMB product.L-band (1452MHz-
1492MHz) penetration capacity of signal is stronger, can be very good to solve the signal covering under the more application scenarios of barrier and asks
Topic.Meanwhile existing DMB receives function and receives III band signal and L-band signal simultaneously.
Existing L-band frequency-variable module is mainly used in the ground installation of satellite communication.In satellite communication ground installation
In, usually use 70MHz or 140MHz IF interface mode.Traditional conversion system is by intermediate-freuqncy signal upward frequency conversion twice
To C or Ku wave band, antenna transmitting is then given after the amplification of excessively high power amplifier；C the or Ku band signal that antenna receives first passes through
Low-noise amplifier amplification is crossed, then through down-frequency conversion twice to 70MHz or 140MHz intermediate frequency.In this conversion system,
The height of local vibration source working frequency required for second of up-conversion of transmission channel and the first time down coversion of receiving channel and frequency
Rate width reaches 500MHz or wider, and complicated circuit design is needed just to be able to satisfy technical requirement.
As the communication technology is grown rapidly, the microwave device suitable for L and LS wave band is more and more abundant, and cost performance is high,
And its power consumption and volume are all smaller and smaller.Therefore it in the ground installation of existing satellite communication, mostly uses intermediate-freuqncy signal
L-band is first upconverted to, then L-band is passed through into a upward frequency conversion to C or Ku wave band, is finally sent after the amplification of excessively high power amplifier
Emit to antenna；C the or Ku band signal that antenna receives first passes through low-noise amplifier and amplifies and be once down-converted to L wave
Section.The frequency conversion unit between 70MHz or 140MHz intermediate frequency and L-band is usually called L-band frequency-variable module.
Existing L-band frequency-variable module generallys use double conversion scheme (Wang Rong, the direct modulation /demodulation frequency converter of L-band
Communicated with L-band frequency converter [J] and radio and television, 2007 (4): 17-20) up-convert the signals to L-band.First time frequency conversion
It is divided into Low Medium Frequency (lower than low-limit frequency) and high intermediate frequency (being higher than highest frequency) scheme, local vibration source is point frequency source.Wherein high intermediate frequency
Scheme is more advantageous to the inhibition of spurious signal and local oscillator leakage signal.Second of frequency conversion local vibration source is frequency source.In double conversion
Two frequency mixers are needed in scheme, two filters, two frequency synthesizers, two crystal oscillators, device used is relatively more, exists
Volume is big, and power consumption is big, is unfavorable for integrated problem.The IF interface that existing L-band frequency-variable module uses for 70MHz or
140MHz.And common reference frequency output is 950MHz-1450MHz, and output frequency bandwidth is 500MHz, it is clear that existing
The L-band frequency-variable module for applying to satellite communication ground installation is not particularly suited in DMB emission system.
Therefore to solve the signal covering problem under the more application environment of barrier, the user's body of DMB product is promoted
Degree of testing, can be in same DMB system, while launching III band signal and L-band signal.In application III band signal
In DMB system, it is further added by the DMB emission system of a set of transmitting L-band signal, it is clear that cost is too high, implements more difficult.
The present invention from low cost, set out by the angle having the advantages of simple structure and easy realization, and design is a to launch III band signal and L simultaneously
The DMB emission system of band signal.
Summary of the invention
In view of this, the purpose of the present invention is to provide a kind of DMB transmitting systems that can emit III wave band and L-band simultaneously
The L-band frequency-variable module of Direct conversion is applied to launch in the DMB emission system of III band signal by system, makes this be
System can launch III band signal and L-band signal simultaneously, to solve the signal covering problem in practical application, promote DMB
The user experience of product reduces cost, simplifies structure, it is easy to accomplish.
In order to achieve the above objectives, the invention provides the following technical scheme:
A kind of DMB emission system that can emit III wave band and L-band simultaneously, comprising: COFDM encoder, upconverter,
Power splitter, III band filter, L-band frequency-variable module, power amplifier and transmitting antenna；The L-band frequency-variable module includes low noise
Amplifier, phase-locked loop frequency source part, Direct conversion module and L-band bandpass filter；Phase-locked loop frequency source part
Including constant-temperature crystal oscillator and phaselocked loop (Phase Locked Loop, PLL)；
In the L-band frequency-variable module, the III band signal come out from power splitter first passes through low-noise amplifier and puts
After big, access Direct conversion part (is based on ADL5350), while the phase-locked loop frequency source part (base that will pass through process control
In ADF4351) the stable local oscillation signal access Direct conversion part of obtained high-frequency, III band signal and local oscillation signal
Mixing is partially completed in Direct conversion；The mixing had both included up-conversion or there are many interference signals including down coversion, while also
Frequency conversion, therefore the good L-band bandpass filter of mixed frequency signal access performance that Direct conversion module exports need to be carried out
Filtering, filtering interference signals.
Further, the COFDM encoder includes sequentially connected convolutional encoder module, time-interleaved module, frequency friendship
Module, DQPSK modulation module and OFDM modulation module are knitted, field programmable gate array (Field-Programmable is passed through
Gate Array FPGA) realize the codings of data to be sent.
Further, successively pass through upconverter, filter and power splitter by the signal that OFDM modulation module is modulated, obtain
Two-way III band signal, III band signal is sent after power amplifier amplifies by transmitting antenna all the way；Another way III wave band
Signal first passes through L-band frequency-variable module and is converted to L-band, is then sent after power amplifier amplifies by transmitting antenna.
Further, the upconverter, III band filter, power splitter and L-band frequency-variable module are integrated in one piece of plank
On.
Further, the upconverter uses AD9957 chip.
Further, the Direct conversion part uses ADL5350 chip, realizes amplified III band signal and this
The mixing of vibration signal, upconverts to L-band for III band signal.
Further, the PLL uses ADF4351 chip, is controlled by program PLL, keeps L-band frequency-variable module defeated
Frequency is adjustable out.
Further, the L-band bandpass filter uses microstrip line hair clip mode filter or cavity body filter.
The beneficial effects of the present invention are:
Existing DMB emission system, can only launch the signal of single frequency band, have very big office in actual application
It is sex-limited.The existing L-band frequency-variable module applied to satellite communication uses IF interface (70MHz or 140MHz), and utilization is secondary
Intermediate-freuqncy signal is upconverted to L-band by conversion system, and structure is complex, is unfavorable for realizing miniaturization, low-power consumption, high integration
Requirement.Direct conversion L-band frequency-variable module is applied to launch III wave band letter by DMB emission system provided by the invention
Number DMB emission system in, make it while launching III band signal and L-band signal, thus solve it is more susceptible in barrier
Signal covering problem under condition promotes the user experience of DMB product, while also meeting low cost, has the advantages of simple structure and easy realization
Requirement.
Detailed description of the invention
In order to keep the purpose of the present invention, technical scheme and beneficial effects clearer, the present invention provides following attached drawing and carries out
Illustrate:
Fig. 1 is DMB emission system structural block diagram of the present invention；
Fig. 2 is L-band frequency-variable module；
Fig. 3 is AD9957 upconverter internal functional block diagram；
Fig. 4 is the receiving end DMB structural block diagram；
Fig. 5 is L-band hair clip type bandpass filter schematic diagram；
Fig. 6 is L-band hair clip type bandpass filter domain；
Fig. 7 is L-band hair clip type band-pass filter effect picture.
Specific embodiment
Below in conjunction with attached drawing, a preferred embodiment of the present invention will be described in detail.
As shown in Figure 1, a kind of DMB emission system that can emit III wave band and L-band simultaneously of the present invention, comprising:
COFDM encoder, upconverter, power splitter, III band filter, L-band frequency-variable module, power amplifier and transmitting antenna；On wherein
Frequency converter, III band filter, power splitter and L-band frequency-variable module are integrated on one piece of plank.The COFDM encoder packet
Include sequentially connected convolutional encoder module, time-interleaved module, frequency interlacing module, DQPSK modulation module and OFDM modulation mould
Block realizes data to be sent by field programmable gate array (Field-Programmable Gate Array, FPGA)
Coding.As shown in Fig. 2, L-band frequency-variable module includes low-noise amplifier, phase-locked loop frequency source part, Direct conversion module
With L-band bandpass filter；Phase-locked loop frequency source part includes constant-temperature crystal oscillator and PLL.
In the L-band frequency-variable module, the III band signal come out from power splitter first passes through low-noise amplifier and puts
After big, access Direct conversion part (is based on ADL5350), while the phase-locked loop frequency source part (base that will pass through process control
In ADF4351) the stable local oscillation signal access Direct conversion part of obtained high-frequency, III band signal and local oscillation signal
Mixing is partially completed in Direct conversion；The mixing had both included up-conversion or there are many interference signals including down coversion, while also
Frequency conversion, therefore the good L-band bandpass filter of mixed frequency signal access performance that Direct conversion module exports need to be carried out
Filtering, filtering interference signals.
Successively pass through upconverter, filter and power splitter by the signal that OFDM modulation module is modulated, obtains two-way III
Band signal, III band signal is sent after power amplifier amplifies by transmitting antenna all the way；Another way III band signal is first
It is converted to L-band by L-band frequency-variable module, is then sent after power amplifier amplifies by transmitting antenna.
Direct conversion part uses ADL5350 chip, realizes the mixed of amplified III band signal and local oscillation signal
Frequently, III band signal is upconverted into L-band.PLL uses ADF4351 chip, is controlled by program PLL, makes L wave
Section frequency-variable module output frequency is adjustable.L-band bandpass filter uses microstrip line hair clip mode filter or cavity body filter, former
Effect is managed as shown in Fig. 5~7.
In the present embodiment, upconverter uses AD9957 device, as shown in figure 3, mainly by digital processing element inside it
It is formed with logic control element.Data processing unit specifically includes that data combined processing unit, anti-CCI (inverse
Cascaded comb integrator filter, interpolation cascade integral comb filter), fixed interpolation filter, CCI can
Program interpolation filter, quadrature modulator, Direct Digital frequency synthesizer DDS, anti-SINC filtering, output amplitude multiplier,
Several parts such as 14 digital analog converter, PLL and the clock controls for being.Logic control element includes: control register, level translation
Control, mode selection logic, scheme control etc..The function of modules is as follows:
(1) data combined processing unit: under quadrature modulator mode, input AD9957 baseband signal be alternate I,
Q component, data combined processing unit need to identify the I/Q data of input, and be isolated, and it is parallel to be converted into I, Q two-way
Data flow is sent to next stage circuit.
(2) fixed interpolation filter: Parallel I/Q two paths of data stream of data combined processing unit output is needed by filtering
Over-sampling is realized in device processing.Fixed interpolation filter is made of 2 grades of half-band filter HBF, is mainly carried out to input data
Fixed interpolation, i.e. interpolation factor is fixed (4 times), and it has low-pass characteristic.Every level-one half-band filter can be improved
One times of sample rate.Meanwhile in order to make signal band be in the flat of filter, generally requires and improve half-band filter
Cutoff frequency.
(3) cascade integrator comb (CCI) filter: being a programmable over-sampling filter.CCI filter be by
Integrator and comb filter two parts cascade composition, interpolation factor R can be with programming Control, that is to say, that it is to data
Interpolation multiple be it is controllable, mobility scale be 2~63 times.Fixed interpolation filter and CCI filter are used cooperatively and can mention
For 8~252 interpolation multiple this be the key that AD9957 device realizes any baseband signalling rate.
CCI filter also has the Frequency Response of low pass, can generate certain decline to the interpolated signal by CCI filter
Subtract, and the different insertion factors can introduce different loss and decaying.The frequency of transmission data also influences whether declining for signal
Subtract the gradient.
(4) anti-CCI filter: AD9957 device in order to eliminate I/Q data flow because of the gradient that decays caused by CCI filter,
It before inputting CCI filter, first to be pre-processed by an anti-CCI filter, to realize the work to this decaying precompensation
With.
(5) quadrature modulator: digital baseband signal is modulated on the carrier wave of required frequency by realization.
(6) DDS: for generating the sine and cosine digital carrier signal of exact quadrature.DDS essence is a kind of frequency divider,
System clock (fsysclk) is divided by programming frequency control word (FTW), is carried with generating the sine and cosine of required frequency
Wave.It exports carrier frequency fout and the relationship of frequency control word (FTW) and system clock (fsysclk) is as follows:
Fout=(FTW*fsysclk)/232
(7) anti-sinc filter: modulated digital signal will be converted into analog signal by the DAC of a 14bit.
(8) output amplitude multiplier: amplitude output signal is controlled with the digital multiplier of a 8-bit.
(9) PLL phase-locked loop module: the frequency to reference clock is realized by the way that corresponding register control word is arranged or is divided
Frequently.
(10) clock control cell: work clock needed for controlling and generating modules as control clock unit, and
Coordinate the work between modules.
Matched with emission system is the wireless receiver of all kinds of multimedia terminals.In practical applications with low-power consumption, height
Integrated level digital broadcasting baseband decoder chip is core, devises low-power consumption, highly sensitive wireless receiving module, and with the mould
Block is core, by different control circuits, is realized to loudspeaker, light emitting diode (Light Emitting Diode, LED)
The driving of each Terminal Types such as screen, liquid crystal display (Liquid Crystal Display, LCD) screen.The DMB that the present embodiment uses connects
Receiving end structure is as shown in Figure 4.
Emission system of the present invention has successfully applied to DMB (digital multimedia broadcasting) the transmitting system of Chongqing Mail and Telephones Unvi
In system, realizes same DMB (digital multimedia broadcasting) emission system and emit two kinds of band signals, improve barrier more
Side, such as the signal covering problem of teaching building ground floor, the user experience is improved spends, and reduces and takes an examination in large size, such as four or six grades of examinations
In accident rate.
Finally, it is stated that preferred embodiment above is only used to illustrate the technical scheme of the present invention and not to limit it, although logical
It crosses above preferred embodiment the present invention is described in detail, however, those skilled in the art should understand that, can be
Various changes are made to it in form and in details, without departing from claims of the present invention limited range.
Claims (8)
1. a kind of DMB emission system that can emit III wave band and L-band simultaneously, which is characterized in that the emission system includes:
COFDM encoder, upconverter, power splitter, III band filter, L-band frequency-variable module, power amplifier and transmitting antenna；The L
Wave band frequency-variable module includes low-noise amplifier, phase-locked loop frequency source part, Direct conversion module and L-band bandpass filtering
Device；Phase-locked loop frequency source part includes constant-temperature crystal oscillator and phaselocked loop (Phase Locked Loop, PLL)；
In the L-band frequency-variable module, the III band signal come out from power splitter, after first passing through low-noise amplifier amplification,
Direct conversion part is accessed, while the local oscillation signal obtained by the phase-locked loop frequency source part of process control being accessed directly
Up-conversion part, III band signal and local oscillation signal are partially completed mixing in Direct conversion；Direct conversion module is exported
Mixed frequency signal access L-band bandpass filter be filtered, filtering interference signals.
2. a kind of DMB emission system that can emit III wave band and L-band simultaneously according to claim 1, feature exist
In the COFDM encoder includes sequentially connected convolutional encoder module, time-interleaved module, frequency interlacing module, DQPSK
Modulation module and OFDM modulation module, by field programmable gate array (Field-Programmable Gate Array,
FPGA the coding of data to be sent) is realized.
3. a kind of DMB emission system that can emit III wave band and L-band simultaneously according to claim 2, feature exist
In the signal by the modulation of OFDM modulation module successively passes through upconverter, filter and power splitter, obtains two-way III wave band
Signal, III band signal is sent after power amplifier amplifies by transmitting antenna all the way；Another way III band signal first passes through L
Wave band frequency-variable module is converted to L-band, is then sent after power amplifier amplifies by transmitting antenna.
4. a kind of DMB emission system that can emit III wave band and L-band simultaneously according to claim 1, feature exist
In the upconverter, III band filter, power splitter and L-band frequency-variable module are integrated on one piece of plank.
5. a kind of DMB emission system that can emit III wave band and L-band simultaneously according to claim 1, feature exist
In the upconverter uses AD9957 chip.
6. a kind of DMB emission system that can emit III wave band and L-band simultaneously according to claim 1, feature exist
ADL5350 chip is used in, the Direct conversion part, realizes being mixed for amplified III band signal and local oscillation signal,
III band signal is upconverted into L-band.
7. a kind of DMB emission system that can emit III wave band and L-band simultaneously according to claim 1, feature exist
In the PLL uses ADF4351 chip, is controlled by program PLL, keeps L-band frequency-variable module output frequency adjustable.
8. a kind of DMB emission system that can emit III wave band and L-band simultaneously according to claim 1, feature exist
In the L-band bandpass filter uses microstrip line hair clip mode filter or cavity body filter.
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| CN201811615635.7A CN109547037B (en) | 2018-12-27 | 2018-12-27 | DMB transmitting system capable of simultaneously transmitting III wave band and L wave band |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811615635.7A CN109547037B (en) | 2018-12-27 | 2018-12-27 | DMB transmitting system capable of simultaneously transmitting III wave band and L wave band |
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| CN109547037B CN109547037B (en) | 2020-09-01 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110429952A (en) * | 2019-06-04 | 2019-11-08 | 广东圣大电子有限公司 | A kind of comprehensive radio-frequency system of Ku wave band |
| CN111815926A (en) * | 2020-05-14 | 2020-10-23 | 中国气象局气象探测中心 | System and method for meteorological data wireless transmission |
| CN112737512A (en) * | 2020-12-17 | 2021-04-30 | 西安电子科技大学 | Design method of ku waveband frequency synthesizer |
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| CN101022435A (en) * | 2006-12-08 | 2007-08-22 | 鲍东山 | Ground mobile multimedia broadcast receiving and transmitting method and systme based on free DAB |
| CN101022440A (en) * | 2006-03-30 | 2007-08-22 | 鲍东山 | Compatiable DAB ground mobile multimedia broadcast receiving and transmitting method and system |
| CN203645687U (en) * | 2013-12-25 | 2014-06-11 | 中国通信建设第二工程局有限公司 | DAB broadcasting system |
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| CN101022440A (en) * | 2006-03-30 | 2007-08-22 | 鲍东山 | Compatiable DAB ground mobile multimedia broadcast receiving and transmitting method and system |
| CN101022435A (en) * | 2006-12-08 | 2007-08-22 | 鲍东山 | Ground mobile multimedia broadcast receiving and transmitting method and systme based on free DAB |
| CN203645687U (en) * | 2013-12-25 | 2014-06-11 | 中国通信建设第二工程局有限公司 | DAB broadcasting system |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110429952A (en) * | 2019-06-04 | 2019-11-08 | 广东圣大电子有限公司 | A kind of comprehensive radio-frequency system of Ku wave band |
| CN110429952B (en) * | 2019-06-04 | 2024-04-19 | 广东圣大电子有限公司 | Ku wave band comprehensive radio frequency receiving and transmitting system |
| CN111815926A (en) * | 2020-05-14 | 2020-10-23 | 中国气象局气象探测中心 | System and method for meteorological data wireless transmission |
| CN112737512A (en) * | 2020-12-17 | 2021-04-30 | 西安电子科技大学 | Design method of ku waveband frequency synthesizer |
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| CN109547037B (en) | 2020-09-01 |
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