CN85101659A

CN85101659A - Television transmission system

Info

Publication number: CN85101659A
Application number: CN 85101659
Authority: CN
Inventors: 默里
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1985-04-01
Filing date: 1985-04-01
Publication date: 1987-01-24
Also published as: CN85101659B

Abstract

Signal form is that video component obtains from video source in the multi-path TV transmitter of time-division, and in the MAC encoder encodes, encoded signals is modulated in frequency modulator, and this modulator also is received from the oscillator signal of oscillator.The output of frequency modulator is added to transmitter through Port Multiplier, for delivering to antenna to the satellites transmits carrier of transmitter.This equipment comprises sound/data message source, they is divided into A and B group, and is added on two Port Multipliers, and the output of this Port Multiplier is added to another Port Multiplier input respectively.The capable synchronization character data of synchronous generator and the data in self information source are all delivered to Data Assembler, and weave into the multi-channel signal data burst of time-division at this.

Description

Television transmission system

The present invention has discussed the television transmission system of time-division multiplex signal, in this system, row in the information frame is made up of digital data pulse string and video signal components, data in the pulse train are from many different information sources, they are made time-division multiplex with the form of information sets and handle, and it is M that the speed of the data in pulse train is produced ^Bit/sThe present invention has also discussed on limited frequency band native system and the equipment that system adopted of using.

Such data transmission system has advised using with the satellite video signal, and sound and other data (except that main video) all transmit with digital form here.

March nineteen eighty-two made Britain will nineteen eighty-two TV programme via satellite directly after the decision of broadcasting (DBS), be the report that chairman's consultancy group embarks relevant transmission technical standard by Authong part.The result of study of this group, i.e. " direct broadcasting-consultancy group via satellite is about the report of transmission technical standard " as recommendation, with Her Majesty's document office name, announces in November nineteen eighty-two.Multi-channel analog components of system as directed＜the C-MAC of (Britain) Independent Broadcasting Authority〉formally passed through DBs, and formally adopted it afterwards.

The C-MAC system has illustrated in the experiment in Independent Broadcasting Authority August nineteen eighty-two and development report 118/82 " television system of MAC-high-quality satellite broadcasting ", A-MAC system (with the relevant previous section of type of sound and other transfer of data) has also been introduced in this report, the performance index of these two systems have been provided in the report suggestiveness, because this system has adopted DBS, will do some correction to the C-MAC system, video waveform variation structurally includes reducing of the reducing of sound/data transfer cycle, colourity, brightness and sound/data length.

Accompanying drawing 1 has provided the cycle of C-MAC TV signal delegation, and every line occupies 64 ^Ws, every line is with 20.25 ^MHZClock rate be divided into many bits or sampling period, every row is about 1296 sampled points.Fig. 1 is from European broadcasting organization (EB _U) 1983.6 report SPB284 " 12 ^GHZSatellite broadcasting 625 row television standards " the 11st page of Fig. 1 fetches in the literary composition, and this paper is it as a reference, and is and also incorporated its content, and the included content order of every row is as follows:

The a=203 bit, synchronously, sound/data (data burst)

B=4 sampled point-ED conversion

C=15 sampled point-main clamp cycle (colorimetric parameter zero)

SCl=6 sampled point-video signal coding gives and stays the backup sampling point

G=354 sampled point-carrier chrominance signal (C)

G=704 sampled point-luminance signal (y)

SCZ=6 sampled point-video signal coding gives and stays the backup sampling point

N=4 sampled point-enter data transaction

Chroma signal component compression ratio in time is 3: 1, makes about 52 ^WsChrominance information be compressed together with the colored color difference signal of the B-y of the R-y color difference signal that transmits on the figure alternate row and interlacing transmission and only account for 17.48 ^Ws(354 sampled points), luminance signal compression ratio in time are 3: 2, so about 52 ^WsMonochrome information be compressed and occupy 34.76 ^Ws(710 sampled point) is for D _BSTransmission, compressed colourity and luminance component are with 27 ^MHThe bandwidth of Z is carried out frequency modulation(FM), and the radio frequency carrier wave utilizes digital audio/data component to do two-phase or quarternary phase-shift keying (QPSK) modulation, present suggestion is, sound/data component should be the packet group demultiplexing, it is on 624 row of each television frame, each packet group contains 751 bits, there are 195 available bits totally 624 to go (in preceding 8 bits of each data pulse string on each row, whenever the data flow that contains 1 bit begins the capable synchronization character with back 7 bits), this can find out in Fig. 2, Fig. 2 fetches from Fig. 2 of EBu report above-mentioned, a packet group is occupied the cycle data of about 195 bits 3.85 in each television line, and whole the 625th row, as introducing in the EBu report, it is loaded with data entirely.In Fig. 2

S-is that row is synchronous.Word

L ₁-L 625-data pulse string every trade number

The scope that the V-vision signal is shared

The Pl-P162-grouping is separated

The data of L625D-in 625 row

Each family utilizes the suitably parabolic antenna and the F frequency converter of size sensing satellite, can realize directly receiving the transmission of DBS, and the F effect of device frequently again is that incoming frequency is transformed to the uHF frequency band.Advise that also some families receive the signal through the cable TV transmission system, this system can transmit other TV programme at one time, and unnecessary independent antenna is arranged.The place very weak for satellite-signal, cable transmission mode obviously are the superiority that it is arranged.For example, these places are originally not plan to want now to that area transmission the place that receives; Requirement has complicated antenna array, and from being positioned at the place of the several satellite received signals on the different resting positions, perhaps being difficult to point to the satellite eminence at antenna has the place of blocking.

The report chapter 7 of part has been read the correlation between DBS and the cable communication system.And also reported the suggestion of Great Britain cable TV association, even C-MAC is chosen to be the DBS transmission standard, they also still have the ability to provide cable service.Provided several examples in that chapter, adapted with C-MAC, the sort signal form can directly transmission on cable system.What present cable communication system adopted is coaxial cable, on the V.H.F frequency band, transmits their TV programme.But some arguements are also arranged at present, and the system that whether will install in the future should equally with many systems adopt optical cable, still still uses coaxial cable on the viewpoint of low construction cost.

Recently people recognize on VHF cable communication system transmission C-MAC signal do not resemble original imagination convenience because this signal 27 ^MHZFrequency band will occupy very big bandwidth, can be with the number of programs of carrying thereby reduced cable system, and especially on the Continental Europe, it only accounts for 7 at present with expansion ^MHZThe channel spacing of the cable channel of bandwidth is conflicted mutually.Owing to can produce short time delay reflection in the system, and the bit rate of such cable system is very low, therefore uses up to 20.25M in cable system ^BitThe speed of/S is transmitted sound/data-signal will produce serious problem.Consider these top suggestions, controlling these signals, to make it be before signal is delivered to cable system in the practical methods of VHF cable system transmission, just C-MAC signal transformation become P _ALThe type signal, such conversion will be lost the advantage of time-division multiplex colourity and brightness, pay in the carrier system in colourity, produce the shortcoming of intersection-colourity and intersection-brightness again, but importantly in order to prevent unofficial reception, in fact received DBS signal is encoded.Fixed TV service is for example given in unofficial reception, and it is the necessary sign indicating number that is situated between earlier before conversion, then the signal after the conversion is encoded again.

Also do not criticize patent No.8306921(PHB32963 down at us to Britain application) in, we advised be overcome the problems referred to above can be with the method for vision signal being made amplitude modulation(PAM) (being compressed chromaticity and luminance signal) with the method for data pulse string broadening (digital audio/data division).Can reduce bit rate like this, it can be modulated on the single carrier wave.This suggestion has reduced desired bandwidth significantly, but it still needs 14 ^MHZBandwidth, so it is actually the frequency band of two channels, wishes that the DBS signal only is included in a cable staff's in the channel approval so this can not cause.

Afterwards people praise taste be if adopt amplitude modulation bandwidth constraints European cable worker desirable 7 ^MHZIn the band, after its compression, the image that the colour that does not have intersection that the shown television image of the video component of MAC system comes from the PAL television signal transmission system, the PAL signal that intersects brightness defect are produced is equally good, if but they are modulated with carrier wave independently respectively owing to the reason of frequency band, data pulse string at the MAC signal still keeps time-division multiplex in the time, still can leave the problem of sound/data.By the suggestion that portion of Deutsche Post proposes, be when 20.25 to cable operated ^MbWhen still keeping four phase signals on the bit rate of/S, all sound/data component is done the accent that is situated between, 20.25 ^MbThe signal of/S can be effectively by 10.125 ^MHZThe symbol of speed is formed, and each symbol is in four electric rates and the information that has two bits.Yet this suggestion has found that the reflection on the cable is very sensitive, and the recovery of Zhong Pin is also very difficult, and signal has only very little level and vertical eye pattern.

Another envelope view is that bit rate is reduced by half promptly 10.125 ^MbtThe symbol of/s speed is formed, and each symbol is in four level and the information that has two bits.Yet this suggestion has found that the reflection on the cable is very sensitive, and the recovery of Zhong Pin is also very difficult, and signal has only very little level and vertical eye pattern.

Another suggestion is that bit rate is reduced by half promptly 10.125 ^Mbt/ s when adopting duo-binary coding (three level signal deliberately has interference between the symbol), just can transmit on cable, and the bandwidth that it requires is 5.0625 ^MHZ, this compares with the C-MAC packet group system that top EBu the report recommends, and it only can transmit half of sound/data component.

The advantage of said system and problem are at the report MDD/KDT/007/84/MA of CCETT." Le Codage MAC/Duobinaire-Adapfation du Signal C-MAC-paguets aux Keseaux Terrestres " the middle work) discuss, article is write 1984.1.19 number institute by M.ALard and Lassalle.

Reduce the speed 10.125 that a large amount of information component can reduce it ^MbtThe shortcoming of the last transmission of/s is that the cable staff must select him to require four information sources that are used for transmitting on cable when receiving the C-MAC signal, according to the suggestion in the EBu data, the practical method that forms the packet group signal from different information sources will be the sound/data source shunt the C-MAC signal, these signals are along separate routes added sign, select the information source with vision signal of four requirements, then before being sent to cable again synthetic these the selected source signals of multichannel (8 sound/data sources are advised with 20.25 in the C-MAC grouping ^MbtThe speed of/s, four sources are the speed of half).

Order of the present invention provides a transmission system, and this system can avoid above-mentioned pointed shortcoming just.

The invention provides a television transmission system, the main signal form of every frame middle row is a time-division multiplex, and it includes digital data pulse string component and video signal components.Data in data pulse string are from various information source, from each information source, they are all formed the pulse group by time-division multiplex, the data transfer rate of data pulse string is Mbit/s, be characterized in and be divided into the N group to signal source, concerning every group, the data from information source are by time-division multiplex, and the series of pulses group of coming from each source forms N son-multichannel signal with the form of data bit flow.

Data bit has been formed corresponding each row of data pulse string, data pulse string bit-by-bit ground, continuously from N data bit stream, obtain and constantly the transmission, its information rate is above-mentioned Mbt/s, and the effective speed of the data of each the information source group in data pulse string is M/N bit/s.Bit quantity in the data pulse string should be the integral multiple of the number N of information source grouping.

The data that said system allows to get from different information sources send out from data pulse string, so in actual applications, and in order to improve the transmission of TV signal on finite bandwidth.Can be from a certain group of data of coming with the single use of TV signal that has improved.

Information source can be divided into two groups, and the consecutive line of each data pulse string is always since first bit of two groups.

The present invention also provides the transmission of television that is used for above-mentioned television transmission system machine equipment, and this system includes the information source of vision signal, and it produces the vision signal of time-division multiplex, and many sound/data-signal information source are pressed Digital Signal Processing to sound/data-signal.In order to obtain time-division multiplexization, digital signal is arranged in as the series of pulses group in the data pulse string component of seeing TV signal as, and its speed is Mbit/s.Be characterized in the information source of sound/data-signal is divided into the N group, the signal that comes from the information source of each information source group for time-division multiplexization constitutes a string bit pulse group with the form of bit stream, thereafter recomposition N son-multiple signals, in order from each of N bit stream, to take out bit and bit signal to be formed data pulse string, make that the speed one by one that the relevant row of data pulse string contains continuously from each of N bit stream is the bit of Mbit/s.And the corresponding data transfer rate of the data institute that requires each group in the data pulse string is M/N hit/s.The sum of the bit in data pulse string is the integral multiple of packet count N.

When the information source of sound/data-signal is divided into two groups, a choice device of choosing bit from each group is arranged, make consecutive line first bit in two groups of each data pulse string begin.

The present invention also further provides the TV receiving apparatus that is used for above-mentioned television transmission system, and it includes the device that TV signal receives, the device of separating video component from TV signal, the device of generation data pulse string signal from TV signal.It is characterised in that receiving equipment has additionally comprised from the data pulse string of representing a specific information source group and send the device of getting bit.This equipment additionally includes again vision signal is modulated to the device that carrier wave gets on, its bandwidth is less than the bandwidth of the signal that is received, this device can be further used for the bit in some information source groups form data rate be M/N h/s correction data pulse string in, also provided the device that data pulse string is modulated to the data pulse string that makes its constitute the time-division multiplex TV signal of video component limited bandwidth on the carrier wave and improved.

Above-mentioned some characteristics with other of the present invention will illustrate that with reference to the accompanying drawings, they are with example:

Fig. 3 is transmitter square figure used in this invention.

Figure 45 67 is used for the timing diagram of key diagram 3 transmitter apparatus work.

Fig. 8 is the calcspar of receiver used in this invention and frequency converter.

Fig. 9 is the comparison detailed block diagram of certain part among Fig. 8.

Figure 10 is the timing diagram of key diagram 9 part operation principles.

Calcspar according to Fig. 3 of the present invention, it is transmitter apparatus, it is used for producing a kind of time-division multiplex television signal form, the video component of transmission equipment is provided by videl signal source 1, and it is added on the MAC video encoder 2, is compressed under the ratio that their require from the brightness of information source 1 and colored color difference signal, arrangement is in time thought reasonably, as figure, shown in 1, suppose the words of not making coding from the MAC video component of encoder 2.If but it still will encode, encode in encoder 2 with any known technology so.This technology is the commentary that just obtains significant recently.Be added on the frequency modulator 3 from the video component of the multichannel of encoder 2, also be added to above it from the Swing signal that shakes of the appropriate frequency of the Swing device 4 that shakes, the bandwidth that the signal that is transmitted is like this occupied on the tranmitting frequency that requires is 27 ^MHZThe modulated output that obtains from modulator 3 is added on the Port Multiplier 5, and its output is delivered on the parabolic antenna 7 by transmitter 6, directly transmits to corresponding satellite.Video signal generating equipment, its structure and work say that relatively everybody knows quite well, and work here and further introduce.

Transmitter, it comprises 8 sound/data source, numbering from 8 to 15, also can number conversely, include a pair of information source that the stereophonic signal that combines with vision signal is provided, also have some that other stereo or single-audio signals are provided in addition, and the data of teletype signal form and be used to supervise the data of showing the space and the information source of other signals.In present introduction, suppose the stereophonic signal that information source 8 and 9 provides two voice signals conducts and optical signal to mix, information source 10 signal of offeing telex, it can be used for mixing captions for vision signal, information source 11 then provides top mentioned aerial prison to show signal, these four information sources are formed first group " A ", among the information source 8-15 each all has input terminal C, it can receive from the corresponding clock signal of clock generator 16 outputs, and the frequency of clock signal and the characteristic of information source adapt.Be added to respectively from the output of information source 8-11 in the input or first packet group Port Multiplier 17 of " A ".Their form second group " B " output of remaining information source 12-15, are added on the input or second packet group Port Multiplier 18 of " B ".

In order to receive from the speed of gate generator 16 outputs is 10.125 ^MHZClock pulse, packet group Port Multiplier 17 and 18 all is added with clock input signal C ₁" A " group Port Multiplier 17 obtains supplied with digital signal from information source 8-11, and the synthetic packet group that has the suitably preceding top guide of form known of these sets of signals, its speed is 10.125 ^Mbit/ s, in the C-MAC packet signal of recommending in the shared time range of the combination of these packet group and the top EBu report that data pulse string occupied was similar.

Fig. 4 is situated between with figure the time relationship that is included in from son-multiple signals that the output of packet group Port Multiplier 17 obtains is described.Bit rate is 10.125 ^MbitDuring/s, it has 98 bits in each row, if each packet group has 751 bits, each packet group will be occupied 7.66 of about delegation so, some conforms to Fig. 2 among Fig. 4, and Fig. 4 has provided the bit on top, and each bit in being expert at is represented with A, the numbering number of the numeral bit of its suffix, L is expert at ₁On, grouping initial, (L was expert at ₈It finishes during this time) represent with two-wire, each frame neutron-multiple signals " A " includes 81 such packet group, 321 vacant bits are arranged in addition, it finishes at 621 row is starting, and by row 622,623 and 624 expansions, so the number of bit rate in each son-multiple signals and packet group is half of number of defined in the above EBu report.The signal that comes from information source 12-15 uses the same method by 18 processing of " B " packet group Port Multiplier, bit number in every row also is 98, per 751 bit groupings groups also approximately occupy 766 row, in this case, in every frame, son-multichannel signal, " B " also contains 81 packet group, the vacant bit that similar number is arranged as son-multiple signals " A ", appears at 621,622,623 and 624.The figure of many-multichannel signal " B " explanation that is situated between.

It should come reference numbers with identical method among Fig. 4 in Fig. 5.

" A " " B "-multichannel composite signal that obtains from packet group multiplexer 17 and 18 is added to the input of Port Multiplier 19 respectively.In order to receive from 20.25 of gate generator 16 ^MHZClock pulse, also be added with input clock signal C on the Port Multiplier 19 ₂, it is 20.25 that multiplexer 19 alternately transmits bit rate ^MHZ1-L " A ", " B " packet group multiplexer 17 and 18 " A " and " B " son-multichannel composite signal are that the multiple signals that make such formation alternately extract from sound/data source 8-15 two groups (A and B) and speed is arranged is 20.25 ^Mbt/ s.Be added in first input of data composer 20 from the output of Port Multiplier 19, it also can be the form of multiplexer.Its second input is connected with the output of synchronization character generator 21, also is added with clock input C3 on the synchronization character generator, and it receives from 20.25 of pulse generator 16 ^MHZThe output clock pulse, synchronization character generator 21 produces 8 bits, the capable synchronization character composition of initial sum 7 bits of 1 bit just, in assembled frame data, it is to be added in the capable front of each sound/data bit.

The 3rd input of Data Assembler 20 is connected with information source 23, it is to be used to make data to occur on 625 row, as (, can be 624 row) introduced in the top EMu report if do some modification by following method, for receive from gate generator 20.25 ^MHZClock pulse, clock input C is arranged on the information source 23 ₄The output packet of data remittance orchestration 20 contains the Frame of the row 1 of C-MAC packet signal to row 625, some difference of suggestion during it and top EBu report, in this suggestion, each bit of data is alternately to obtain from information source, the valid data of every row partly are 196 rather than former 195 bits of suggestion, but the data message of row synchronization character and row 625 is former forms, its output is the input as the 2-4PSK modulator, in order to produce phase shift keyed signal, another input connects Zhen Swing device 4, receives Zhen Swing signal, phase shift keyed signal is added on the Port Multiplier 5, makes this modulating data can insert in suitable time slot in the C-MAC packet group signal and goes.

Fig. 6 has provided the compilation form of data bit in the Frame, and sound/data bit always begins with information source group A on each row, and B finishes with the information source group, makes to include 98 " A " bits and 98 " B " bits in every row.Along with valid data cycle of every row is increased to 196 bits from 195, if the cycle of every row is still contained 1296 sampling periods, so the number of the bit of the remainder of Hanging or sampling need change.So suggestion will reduce a bit a little, and the transient period increases a bit slightly for the number in video signal components sampling period.The form relevant with figure will be done some following modification:

A=204bit, synchronously, sound/data (data pulse string)

The b=5 sampled point, the ED conversion

The C=15 sampled point, the status of a sovereign cycle (zero level of chroma reference)

The SC1=5 sampled point, video coding is reserved back-up

The d=352 sampled point, colourity (C)

The g=704 sampled point, brightness (Y)

SC ₂=6 sampled points, video coding is reserved back-up

The h=5 sampled point enters data transaction

By noted earlier, whole the 625th provisional capital is loaded with data, and Fig. 7 a has provided the structure of row, wherein:

FSD=104bit, the frame synchronization data

UDT=5bit, unified data and time standard

SDF=94bit, fixing Frame

RDF=470bit, the Frame of repetition, it contains the number of 5 94 bits

According to pulse group TDM(TL(1)

-(5)-time-division multiplex control group

NA=564bit, the data pulse group of 6 94 bits, not appointed.

UDF=59bit, undefined

Frame synchronization data (FSD) contain:

LSW=8bit, 1 bit are situated between and transfer the device work of entering to add 7 bit-rows synchronization characters

CRI=32bit, clock enters work

The FSW=64bit frame alignment word

For desired data in the 625th row are received in the frequency mixer of cable front end with 1/2 bit rate in line period, another suggestion is will be to a little modification of row 624,625 row, shown in Figure 76.According to present system, transmit static Frame (SDF) in the cycle of suggestion row 624, and in this cycle data, stay 102 bits and do not make definition (uDF ₁), its valid data cycle is not obtained sound/digital signal from the 8-15 information source.The 625th capable being revised as is not with static data frame signal (SDF), but continues to be loaded with other information.The 625th the row end undefined cycle (uDF ₂) being increased to 153 bits, the reason of this variation will illustrate below.

Fig. 8 is the calcspar of receiver, and it has a frequency mixer, and it can be transformed into the C-MAC TV signal of introducing above that receives and be suitable for the TV signal that cable communication system adopts.Provided parabolic antenna 31 among the figure, in order to receive C-MAC packet group DBS TV signal, it should have suitable size dimension, and the DBS TV signal specifies in the broadcast band of 12GHZ.What join with antenna is down-conversion mixer 32, and the frequency of input signal is shifted in the uHF broadcast band in frequency mixer, greatly between 950-1750MHZ.They can be delivered on the input terminal 34 of receiver through coaxial cable 33 like this.In receiver, the signal of terminal 34 is delivered to tuned cell 35, and here it mixes to produce intermediate-freuqncy signal (if) mutually with local oscillation signal, and this moment, its intermediate frequency was 134MHZ.Adopt the method for this passband just can select the TV signal that requires.The bandwidth of the intermediate-freuqncy signal of tuner and generation is 27MHZ, and just in time the bandwidth with DBS is consistent for it.Tuned cell 35 adopts selects voltage method to finish tuning work, this voltage be added to link to each other with selector (not drawing) unit 36 on, it is again as first input of adder circuit 37.The output of add circuit is connected on the corresponding input of tuner 35.Add circuit also has second input, is added with automatic frequency control (afc) voltage of sending here through line 38 on this.AFC voltage is added on the selection control voltage, to guarantee the correctly tuning of tuned cell 35.Be exaggerated at amplifying stage 39 from the intermediate-freuqncy signal of tuned cell 35, be added to then on the surface acoustic wave Lu ripple device 40, the centre frequency of this Lu ripple device is 134MHZ, normally 27MHZ.The output of surface acoustic wave Lu ripple device 40 is baseband video signal MAC, in the level 42 of postemphasising to signal postemphasis handle amplitude limit with Frequently level 41 produces afc voltage, and it is delivered on the add circuit 37 through 38.

Intermediate-freuqncy signal also is added to amplitude limiter and 2-4PSK Jie transfers on the device 43, and data pulse string in 43 (sound/data component) and other the digital information on 20.25Mbit/s all have been resumed out.These digital signals are delivered on the converter 44, and converter 44 has many functions, and one of them is the bit that replaces that launches sound/data digital signal, makes their bit rate fall very lowly.Fig. 9 has at length provided some feature of converter 44.The digital information of 20.25Mb/s is added to the input S of converter 44 in Fig. 9 ₂On, it can be used as the input of pulse generator 45, and pulse generator produces desired various clock frequencies of circuit and various read-write control signal, and these read-write control signal also are that converter 44 proper operations are necessary.In order to receive 196 sound/data bits of every row, its clock rate is C ₁20.25MHZ 52 input is also delivered on the shunt circuit 46 simultaneously.At second clock frequency C ₂10.125MHZ control under, the output of shunt circuit 46 is pulses of the alternate of coming from the input data, promptly only is bit of ' A ' group or the bit of ' B ' group, as shown in Figure 6.The output of supposing shunt circuit 46 only comprises ' A ' bit, it is added on a latch and the delay circuit 47, at this moment the length of each bit is doubled and as described below, they will have a very short time delay, and circuit 47 also receives the clock signal C2 of 10.125MHZ.

Data on the terminal 52 are delivered on the fifo circuit (FIFO) 48, regulation L624/625 is FIFO, circuit is operated the valid data in every frame the 624th and 625 row, takes out to be adapted at the data division that transmits on the low rate of 10.125Mb/s, and FIFO receives C by its frequency separately ₁And C ₂Clock.Terminal 52 also is connected with synchronous circuit 49, and it is at clock frequency C ₁And C ₂Control under from the capable synchronization character that receives, extract synchronizing information, known that the synchronization character sequence just can produce suitable synchronization character on the desirable time, its speed is 10.125Mb/s.Below this point to be described, please refer to Figure 10.Synchronous circuit 49 produces timing controling signal from input the synchronization character, and its is through line 50 another input as pulse generator 45, and it is the appearance of the read-write that produced of control impuls generator accurately.

The output of latch and delay circuit 47, the output of L624/625FIFO48 and synchronous circuit all links to each other with the input of Port Multiplier 51 respectively, the control of the control signal by pulse generator 45, its produces the data of data pulse string and row 625, and their speed is half of speed of C-MAC packet group.Speed in the output 53 is 10.125Mb/s.With regard to the data on these row, how to realize the data of ' A ' and ' B ' Port Multiplier are sent out, we can be illustrated with corresponding timing Figure 10.Figure 10 has at length provided certain part of adjacent lines, it consists of the following components: be transformed into 5 sampling periods (h) that data begin, 204 bits synchronously and sound/data (pulse train) (a) be converted to 5 sampling periods (b) of end with data, the speed of all these is 20.25Mb/s all, referring to Fig. 1.Synchronously and 204 bit numbers of sequeling of data/sound, represent to enter synchronously bit 2-8(S with the bit of K mark) the corresponding 7 bit-rows synchronization characters of formation.From 9 to 204 remaining bits carry sound/data-signal with band, and its odd number bit is loaded with the data of ' A ' group information source, and even bit then is the data of ' B ' group.For a certain definite modulation format, cycle might not be needed (h) and (b), it also can be loaded with data like this, if bit rate reduces by half, bit number can be increased to (h+a+b)/2=214/2=107 from 9/2=204/2=102, concerning synchronization character, might not transmit entering (Kun-ir) bit K and just may be used for valid data to 98 bits.The transmission of data now can be since cycle h initial, but can see from Figure 10 a, the synchronization character of the row that we were concerned about just began afterwards in the cycle (h), this problem can overcome with the capable synchronization character that is produced by synchronous circuit 49, and (this point was done introduction with entering bit (run-in) in front) is shown in Figure 10 b.The numbering of bit is consistent with the numbering of the bit of the data pulse string of Figure 10 a in Figure 10 b.Latch and delay circuit 47 blockades or broadening are from each ' A ' bit of Port Multiplier 46, and producing speed is ' A ' bit pulse string of the broadening of 10.125M/s, and on this speed, it has the time delay of 1 bit.First broadened ' A ' bit be along with the 7th broadening of front bit sync word, this ' A ' bit is designated as A9, it has indicated that the reception of input data bit begins with it, this also can use on other ' A ' bit.' A ' bit (A201 and A203) last in the data is as back-up, and it can expand in transformation period (b), and the width in cycle (b) is half of cycle of broadening.So as can be seen, row synchronization character and data ' A ' bit fully can be by cycle h, and a and b hold.

Except receiving the data in terminal 52, the output S.FIFO that L624/625FIFO48 also receives synchronous circuit 49 is the broadening synchronization character suitably, it can be used with row 624/625, and it is positioned the section start of broadening capable 624/625, it will partly start in the beginning of cycle h.What relation is the data of coming from these row do not have with the row of front, it be simply with broadening speed read in the first in first out unit, this just means that it can not comprise all data in 624 and 625 of may being expert at that occur with the broadening form.By the discussion of front, suggestion is revised row 624 and 625, so even without valid data in these row, do not had what problem yet.In line period, make broadening, static data frame (SDF) is moved on to the 624 valid data parts of going, in 624 row, also will allow to hold frame synchronization data (FSD), unified data and time standard (uDT) and the frame data (RDF) that repeat.Except the top output 53 that is produced by converter 44, another output 54 provides) clock pulse of a 10.125MHZ.

Referring again to Fig. 8, the modulation input of delivering to modulator 55 from level 42 vision signals that obtain of postemphasising, on carrier wave, this carrier wave is from carrier oscillator 56 by amplitude modulation(PAM) for signal in modulator, and it is as second input of modulator.The frequency of carrier wave is in the frequency band range that adopts at cable communication system.The output of modulator 55 is added to first input of Port Multiplier 57, and for signal is delivered to cable communication system, the output of Port Multiplier 57 is added in the output 59 of power converter cells by residual sideband Lu ripple device 58.

The digital signal that transmits broadening respectively is added on the digital modulator 60 with the converter terminal 53 of relevant clock frequency signal (10.125MHZ) and 54 output, and another input of modulator 60 is to receive the carrier signal of coming with carrier oscillator 56.In modulator 60, the digital signal digital modulation that carrier wave is broadened, it can be duo one a binary modulated form, is added on second input of Port Multiplier from the transferred signal of modulator 60, then signal is delivered on the outlet terminal 59 by Lu ripple device 58.

For only transmitting the continuous receiver of cable system of ' A ' group data, the receive mode that is used in the C-MAC packet group receiver that provides in the reception of data-signal and the suggestion in the existing transmission system does not have any very big difference, and the speed of C-MAC reduces by half.Directly the receiver from satellite reception data-signal requires that a splitter is arranged, and it will be divided into two groups ' A ' and ' B ' to data again.Its advantage is that signal is changed to (10.125MHZ rather than 20.25MHZ) on the lower speed, and the data processing ratio is easier to.Utilize following method can obtain being used for the reference receiver of the dual work of cable/satellite easily,, and between with satellite and the branch circuit-switched data that obtains from cable, be added with suitable switch promptly by top said the need with two data accent devices that are situated between.

The output bit flow of Port Multiplier 19 is to constitute with the form of continuous signal bit data set in the concrete equipment in front.Very clear, can use the many bits that produce by same Port Multiplier to constitute each data set.

Errata

CPEL855180

Errata

CPEL855180

Claims

1, in the television transmission system of time-division multiplex signal, the fundamental component of its frame middle row is digitized data pulse component and video component.From the data in data pulse string of many various information sources with the formation of continuous impulse group by time-division multiplex, the data rate of data pulse string is Mbit/s.The characteristics of system are that its information source can be divided into N information source group, and the data of coming with the information source of each information source group are with the form time-division multiplex of consecutive pulses group, and they form N son-multiple signals with the form of data bit flow.With the data bit of each data pulse string that the comes formation corresponding line in N the data bit stream, its speed is Mbit/s.Bit number in pulse train is the integral multiple of information source packet count N.

2, by claim 1 described television transmission system, it is characterized in that and can be divided into two groups to information source, the consecutive line of each data pulse string always with two groups in first bit together initial.

3, the TV transmissioning equipment that is adopted in the television transmission system by above-mentioned claim includes the video source that forms the time-division multiplex vision signal, many information sources of sound/data-signal.It includes device that sound/data-signal is handled as digital signal and digital signal is made the device that time-division multiplex is handled by the form of continuous impulse group.The time-division multiplex signal is in the TV signal data pulse train, and its speed is M bit/s.The characteristics of TV transmissioning equipment are that sound/data source is divided into the N group, its feature is that also the signal that its handlebar comes with each information source group carries out the device that time division multiplexed is handled with the form of successive bits pulse group, it forms N son-multiple signals with the form of data bit flow, have with each device choosing bit and these bit layouts are become pulse train in N the bit stream, it makes the bit that includes in the corresponding line of data pulse string from N bit stream to come in each, its speed is the initial such Mbit/s of being that introduces, and the bit number in data pulse string is the integral multiple of packet count N.

4, described by claim 3, TV transmissioning equipment is characterized in that and can be divided into two groups to sound/data source, with a choice device is arranged, this device can be chosen bit in each information source group, and each data consecutive line first bit in two groups is begun.

5, the receiving system that includes TV signal by the TV receiving apparatus of claim 1 and 2 described television transmission systems is with the device of separating video signal in the TV signal with to produce the device of data pulse string in the TV signal.The characteristics of receiving equipment are to add in the equipment device of choosing bit from the data pulse string of representing certain specific information source group is arranged.

6, include by claim 5 described TV receiving apparatus vision signal is modulated at device on the carrier wave again, its carrier bandwidths is littler than the bandwidth of the signal that receives.The feature of TV receiving apparatus also is reflected on other devices that provided, and as the bit that comes from an information source group being formed the device of a data pulse string of having revised, its data transfer rate is M/N bit/s; Data pulse string is modulated to the device that forms another time-division multiplex TV signal on the carrier wave, and this signal is the limited vision signal of frequency band and has aligned the data pulse string of speed.