CN108574813A - The protection circuit of high-definition multimedia interface HDMI - Google Patents
The protection circuit of high-definition multimedia interface HDMI Download PDFInfo
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- CN108574813A CN108574813A CN201710139311.XA CN201710139311A CN108574813A CN 108574813 A CN108574813 A CN 108574813A CN 201710139311 A CN201710139311 A CN 201710139311A CN 108574813 A CN108574813 A CN 108574813A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/41—Structure of client; Structure of client peripherals
- H04N21/426—Internal components of the client ; Characteristics thereof
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/765—Interface circuits between an apparatus for recording and another apparatus
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- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
Abstract
The invention discloses a kind of protection circuits of high-definition multimedia interface HDMI.The protection circuit of the high-definition multimedia interface HDMI includes wireless receiving module, signal processing module and Signal interface module.The wireless receiving module receives the radiofrequency signal for carrying audio and video business.The radiofrequency signal that the signal processing module receives the wireless receiving module carries out TDS OFDM demodulations, decoding and synchronization process, obtains audio-video signal, and export the audio-video signal.The Signal interface module receives the audio-video signal of the signal processing module output.The protection circuit of the high-definition multimedia interface HDMI of the present invention can receive and handle with high reliability radiofrequency signal to obtain the audio-video signal of high quality, and device integration is high, have convergence error small, the short advantage of convergence time.
Description
Technical field
The present invention relates to digital TV technologies, relate more specifically to a kind of protection of high-definition multimedia interface HDMI
Circuit.
Background technology
Currently, digital television terrestrial broadcasting（Digital Television Terrestrial Broadcasting,
DTTB）The achievable stage is had reached, the DTTB transmission standards announced on our times mainly there are 3 kinds：U.S.Advanced Television system
The system committee（Advanced Television System Committee, ATSC）The ATSC standards of formulation, the number in Europe
Video Broadcasting-Terrestrial（Digital Video Terrestrial Broadcasting-Terrestrial, DVB-T）, Japan
Terrestrial Integrated Service digital broadcasting（Integrated Service Digital Broadcasting-Terrestrial,
ISDB-T）.Based on the further investigation to this 3 kinds of terrestrial digital television systems, Tsinghua University proposes based on time-domain synchronous orthogonal
Frequency division multiplexing（Time Domain Synchronous Orthogonal Frequency Division Multiplex, TDS-
OFDM）The ground digital television broadcast transmission system of modulation technique, and adopted by China, be established as the DTTB standards in China, life
Entitled " ground digital multimedia TV broad cast（Terrestrial Digital Multimedia Television
Broadcasting, DMB-T）Transmission system ".
DMB-T Transmission systems use following items major technique：
The orthogonal multiple carrier technology of Domain Synchronous.The greatest difficulty of terrestrial wideband wireless transmission is that frequency caused by multipath selects
Property decline, OFDM technology then in terms of contrary frequency Selective intensity have unique advantage.However, the orthogonality between subcarrier
Strict requirements are proposed to synchronous.Europe forms its core technology using full frequency-domain processing mode --- the OFDM of coding（Coded
Orthogonal Frequency Division Multiplex, COFDM）Technology, since its system synchronization and channel estimation are mutual
For condition, the technical measures such as complicated iterative algorithm and high power synchronizing pilot need to be used.And TDS-OFDM passes through time domain and frequency domain
Mixed processing simply and easily realizes quick code word capture and steady synchronized tracking.
Pseudo-random sequence (Pseudo-Noise, PN) filling technique of protection interval.In order in multidiameter delay spread channels
In avoid intersymbol interference, DVB uses the OFDM protection intervals of cyclic prefix filling, and the efficiency that it is transmitted is made to lose.
DMB-T has invented the high protection synchronous transmission technology based on PN sequence spread spectrum techniques, its is used in combination to fill OFDM protection intervals, make be
The spectrum utilization efficiency of system improves 10%, and has 20dB or more synchronous protection gains.
Fast Channel estimation technique.It is longer for the iterative channel estimation process of existing terrestrial DTV transmission standard
（Actual parameter estimation about needs 1.024ms）Deficiency, DMB-T use new TDS-OFDM channel estimation techniques, by just
Related and Fourier transform is handed over to realize Fast Channel estimation（Actual parameter estimation about needs 0.6ms）, improve system movement
Receptivity.
The error correcting technique that forward error correction coding is combined with phase mapping.For the noise using multicarrier COFDM technologies
The reality more poor with respect to VSB single-carrier technologies than thresholding, DMB-T have invented a kind of new system cascade error correction Internal Code and minimum Europe
Family name's distance maximizes mapping techniques, makes to obtain 10% or more improvement using the system signal noise ratio thresholding of multi-transceiver technology.
With the frame structure of Absolute Time Synchronization.DMB-T transport protocols devise the multi-frame structure with Absolute Time Synchronization, side
Just automatic wake-up function is arranged, and reaches power saving purpose, supports portable reception；It is same to be conducive to single frequency network with Absolute Time Synchronization mechanism
Step sends the function control of signal, and DMB-T single-frequency network synchronizations equipment is made to be easier to realize than the same category of device of international existing standard.
Its physical channel frame structure is as shown in Figure 1：
Frame structure is classification, and a basic frame structure is known as a signal frame.Frame group is defined as 255 signal frames, and first
Frame definition is frame group head.Signal frame in frame group has unique frame number, and from 0 to 254, signal frame number (then) is encoded into be worked as label
In the frame synchronization sequence of front signal frame.Superframe is defined as one group of frame group, and the top layer of frame structure is known as superframe group.Superframe is numbered,
From 0 to largest frames group number.Hyper Frame Number (SFN) is encoded into superframe group number (SFGN) in first frame group head of superframe together.
SFGN is defined as the calendar date of superframe pocket transmission, and superframe group is repeated cyclically using a consecutive days as the period, its quilt
The first two byte being encoded in first frame group head of a superframe in downgoing line superframe group.In Beijing time 00：00：
00AM, physical channel frame structure are reset and start a new superframe group.One signal frame consists of two parts：Frame synchronization and
Frame.Frame synchronization is identical with the baseband signalling rate of frame, it is specified that being 7.56MSps.Frame synchronizing signal using walsh codes with
Machine sequence, to realize more identification of base stations.Frame synchronization include preamble, frame synchronization sequence with it is rear synchronous.For a signal frame group
In different signal frames, have different frame synchronizing signals.So frame synchronization can be as the frame synchronization spy of a distinctive signal frame
Sign and for identification.Frame synchronization uses binary phase shift keying（Binary Phase Shift Key, BPSK）Modulation is to obtain
Stable synchronization.
System information transmits.DMB-T transport protocols are that the signal frame of each 500 μ S information data of length sets uniqueness
The frame head of address facilitates the identification and separation of data information, has the technical foundation of fusion multi-service broadcast.
Currently, Tsing-Hua University is directed to the above-mentioned technology of DMB-T Transmission systems, apply for that patent name is " ground digital multimedia
Television broadcasting system ", the patent of Patent No. 00123597.4.The patent diselosesll：A kind of T-DMB electricity
Viewing system, as shown in Figure 2 comprising：One network control center 10, at least one transmitter 20 and at least one receiver
30, the digital code stream transmitted is at least transmitted the first and second signal frames to transmitter 20 from the network control center 10,
Received signal modulation is emitted in the air by transmitter 20, is received by receiver 30.
For TDS-OFDM modulation techniques, modulation step includes the core technology that above-mentioned Tsing-Hua University's patent uses：A, it inputs
The IDFT data blocks that MPEG-TS code streams are 3780 in frequency domain formation length after channel coding is handled；B, using DFT by IDFT
Data block is transformed to the time domain discrete sample value frame that length is 3780,7.56M/s sample value；C, it is inserted into the protection interval of OFDM
The PN sequences that length is 378 are as frame head；D, frame head and frame are combined into the signal frame that time span is 550；E, using tool
The FIR low pass filter of linear phase-delay characteristic carries out frequency-domain shaping to signal；F, baseband signal is subjected to up-conversion tune
It makes in RF carrier wave.
It can be seen from the above, proposing a kind of T-DMB television system and its transmission for DMB-T at present
Scheme, but receive the RF carrier wave of Transmission system transmission for user side, and audio-video signal obtained to the processing of RF carrier wave,
The better solution of neither one.
Now, due to the display terminal resolution ratio of " high definition " digital television in T-DMB television system
Reach 1920 × 1080 pixels, visual effect number is cost-effective, therefore demand of the people to " high definition " digital television is constantly in
Reveal growing trend.However, current digital TV in high resolution handles audio-video signal to RF carrier wave due to the above reasons,
There is also deficiencies for aspect.Therefore, it is necessary to provide it is a kind of can high reliability receive and process the high-resolution multimedia of RF carrier wave and connect
The method that high resolution audio and video accesses in the protection circuit and interactive digital television front end system of mouth HDMI.
Invention content
The object of the present invention is to provide a kind of protection circuit of high-definition multimedia interface HDMI, energy high reliability receives simultaneously
RF carrier wave is handled to obtain the audio-video signal of high quality.
To achieve the goals above, the protection circuit of high-definition multimedia interface HDMI provided by the invention includes wirelessly connecing
Receive module, signal processing module and Signal interface module.The wireless receiving module reception carries penetrating for audio and video business
Frequency signal.The radiofrequency signal that the signal processing module receives the wireless receiving module carries out TDS-OFDM demodulation, solution
Code and synchronization process, obtain audio-video signal, and export the audio-video signal.The Signal interface module receives the signal
The audio-video signal of processing module output.
In one embodiment of the invention, the signal processing module includes demodulation module, decoder module and synchronization
Recovery module.The demodulation module carries out TDS-OFDM demodulation to the radiofrequency signal for carrying audio and video business, obtains base
Band signal.The baseband signal that the decoder module demodulates the demodulation module is decoded, and obtains the audio-video code stream.
The synchronous recovery module carries out the audio-video code stream of decoder module decoding output in time domain and/or frequency domain same
Step.
Preferably, the demodulation module include carrier recovery unit, TDS-OFDM demodulating units, channel estimating unit and
Synchronous recovery unit.The radio frequency for carrying audio and video business that the carrier recovery unit is received from the wireless receiving module
Carrier signal of the extraction for TDS-OFDM demodulation in signal.The TDS-OFDM demodulating units use the carrier recovery unit
The carrier wave for restoring to obtain demodulates the radiofrequency signal received, obtains baseband signal.The channel estimating unit is according to institute
It states the radiofrequency signal that wireless receiving module receives and carries out channel estimation, to be demodulated to the TDS-OFDM demodulating units
Baseband signal compensates.The synchronous recovery unit restores the synchronous letter for the radiofrequency signal that the wireless receiving module receives
Breath.
Preferably, the decoder module includes deinterleaving unit and error correction decoding unit.The deinterleaving unit is to institute
It states the baseband signal after demodulation module demodulation and is deinterleaved transformation, and output transform data.The error correction decoding unit utilizes
Error correction decoding algorithm is decoded the transformation data of the deinterleaving unit output, obtains audio-video signal.
In one embodiment of the invention, the wireless receiving module includes an antenna.
Compared with prior art, the protection circuit of high-definition multimedia interface HDMI of the invention can pass through wireless receiving mould
Block receives radiofrequency signal with high reliability, and handles radiofrequency signal with high reliability by signal processing module to obtain high quality
Audio-video signal.In addition, the protection circuit of high-definition multimedia interface HDMI of the present invention is by by wireless receiving module and tool
There is the signal processing module of demodulating and decoding function to integrate, improves level of integrated system.It is wirelessly connect in addition, the present invention uses
The mode entered receives radiofrequency signal, saves the use of a large amount of cables or optical cable, reduces networking cost, while also saving use
Family circuit, reduces user cost.
By description below and in conjunction with attached drawing, the present invention will become more fully apparent, these attached drawings are for explaining the present invention
Embodiment.
Description of the drawings
Fig. 1 is prior art physical channel frame structure schematic diagram.
Fig. 2 is prior art T-DMB television system block diagram.
The structure diagram for the protection circuit that Fig. 3 is high-definition multimedia interface HDMI of the present invention.
The structure diagram of the signal processing module for the protection circuit that Fig. 4 is high-definition multimedia interface HDMI shown in Fig. 3.
Fig. 5 is the flow chart for the method that high resolution audio and video accesses in interactive digital television front end system of the present invention.
Specific implementation mode
The embodiment of the present invention described referring now to the drawings, similar element numbers represent similar element in attached drawing.
With reference to figure 3, the protection circuit of high-definition multimedia interface HDMI of the present embodiment a kind of includes wireless receiving module
110, signal processing module 120 and Signal interface module 130.The reception of the wireless receiving module 110 carries audio and video industry
The radiofrequency signal of business.The wireless receiving mould 110 includes antenna.The signal processing module 120 is by the wireless receiving module
110 radiofrequency signals received carry out TDS-OFDM demodulation, decoding and synchronization process, obtain audio-video signal, and exporting should
Audio-video signal.The Signal interface module 130 receives the audio-video signal of the output of the signal processing module 120.
In detail, with reference to figure 4, the signal processing module 120 includes demodulation module 121, decoder module 122 and synchronizes
Recovery module 123.The demodulation module 121 carries out TDS-OFDM demodulation to the radiofrequency signal for carrying audio and video business,
Obtain baseband signal.The baseband signal that the decoder module 122 demodulates the demodulation module 121 is decoded, and obtains institute
State audio-video code stream.The synchronous recovery module 123 to the decoder module 122 decoding output the audio-video code stream when
Domain and/or frequency domain synchronize.
The demodulation module 121 of the signal processing module 120 includes carrier recovery unit 121b, TDS-OFDM demodulating unit
121a, channel estimating unit 121c and synchronous recovery unit 121d.The carrier recovery unit 121b is from the wireless receiving
Carrier signal of the extraction for TDS-OFDM demodulation in the radiofrequency signal for audio and video business that module 110 received carry.Institute
The carrier wave that TDS-OFDM demodulating units 121a is restored using the carrier recovery unit 121b is stated to believe the radio frequency received
It number is demodulated, obtains baseband signal.The channel estimating unit 121c is penetrated according to what the wireless receiving module 110 received
Frequency signal carries out channel estimation, to be compensated to the TDS-OFDM demodulating units 121a baseband signals demodulated.Institute
State the synchronizing information that synchronous recovery unit 121d restores the radiofrequency signal that the wireless receiving module 110 receives.
The decoder module 122 of the signal processing module 120 includes deinterleaving unit 122a and error correction decoding unit
122b.The unit 122a that deinterleaves is deinterleaved transformation to the baseband signal after the demodulation of the demodulation module 121, and exports
Convert data.The error correction decoding unit 122b is using error correction decoding algorithm to the transformation number of the deinterleaving unit 122a outputs
According to being decoded, audio-video signal is obtained.
With reference to figure 5, the method that high resolution audio and video accesses in interactive digital television front end system of the invention includes as follows
Step：（1）Receive the radiofrequency signal (step S1) for carrying audio and video business；（2）It extracts and is used for from the radiofrequency signal
The carrier signal (step S2) of TDS-OFDM demodulation;（3）The radiofrequency signal received is demodulated using the carrier wave, is obtained
Baseband signal (step S3);（4）Channel estimation is carried out according to the radiofrequency signal, to be compensated to the baseband signal
(step S4);（5）The synchronizing information (step S5) of the radiofrequency signal received described in recovery；（6）The baseband signal is carried out
Deinterleave transformation, and output transform data (step S6)；（7）The transformation data are decoded using error correction decoding algorithm,
Obtain audio-video signal (step S7)；（8）The audio-video code stream is synchronized (step S8) in time domain or/and frequency domain；（9）
The audio-video signal (step S9) is exported to terminal.
Above in association with most preferred embodiment, invention has been described, but the invention is not limited in implementations disclosed above
Example, and modification, equivalent combinations that various essence according to the present invention carry out should be covered.
Claims (5)
1. a kind of protection circuit of high-definition multimedia interface HDMI, including：
Wireless receiving module, the wireless receiving module receive the radiofrequency signal for carrying audio and video business；
Signal processing module, the radiofrequency signal that the signal processing module receives the wireless receiving module carry out TDS-
OFDM demodulation, decoding and synchronization process obtain audio-video signal, and export the audio-video signal；And
Signal interface module, the Signal interface module receive the audio-video signal of the signal processing module output.
2. the protection circuit of high-definition multimedia interface HDMI as described in claim 1, it is characterised in that：The signal processing
Module includes：
Demodulation module, the demodulation module carry out TDS-OFDM demodulation to the radiofrequency signal for carrying audio and video business, obtain
To baseband signal；
Decoder module, the baseband signal that the decoder module demodulates the demodulation module are decoded, and are obtained the sound and are regarded
Frequency code stream；And
Synchronous recovery module, the synchronous recovery module is to the audio-video code stream of decoder module decoding output in time domain
And/or frequency domain synchronizes.
3. the protection circuit of high-definition multimedia interface HDMI as claimed in claim 2, it is characterised in that：The demodulation module
Including：
Carrier recovery unit, what the carrier recovery unit was received from the wireless receiving module carries audio and video business
Carrier signal of the extraction for TDS-OFDM demodulation in radiofrequency signal;
TDS-OFDM demodulating units, the carrier wave pair that the TDS-OFDM demodulating units are restored using the carrier recovery unit
The radiofrequency signal received is demodulated, and baseband signal is obtained;
Channel estimating unit, the channel estimating unit carry out channel according to the radiofrequency signal that the wireless receiving module receives
Estimation, the baseband signal to be demodulated to the TDS-OFDM demodulating units compensate;
Synchronous recovery unit, the synchronous recovery unit restore the synchronous letter for the radiofrequency signal that the wireless receiving module receives
Breath.
4. the protection circuit of high-definition multimedia interface HDMI as claimed in claim 2, it is characterised in that：The decoder module
Including：
Unit is deinterleaved, the unit that deinterleaves is deinterleaved transformation to the baseband signal after demodulation module demodulation, and
Output transform data；And
Error correction decoding unit, the error correction decoding unit is using error correction decoding algorithm to the transformation number of the deinterleaving unit output
According to being decoded, audio-video signal is obtained.
5. the protection circuit of high-definition multimedia interface HDMI as described in claim 1, it is characterised in that：The wireless receiving
Module includes an antenna.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710139311.XA CN108574813A (en) | 2017-03-09 | 2017-03-09 | The protection circuit of high-definition multimedia interface HDMI |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710139311.XA CN108574813A (en) | 2017-03-09 | 2017-03-09 | The protection circuit of high-definition multimedia interface HDMI |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108574813A true CN108574813A (en) | 2018-09-25 |
Family
ID=63578197
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710139311.XA Pending CN108574813A (en) | 2017-03-09 | 2017-03-09 | The protection circuit of high-definition multimedia interface HDMI |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108574813A (en) |
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2017
- 2017-03-09 CN CN201710139311.XA patent/CN108574813A/en active Pending
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Application publication date: 20180925 |
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| WD01 | Invention patent application deemed withdrawn after publication |