FI108385B - Procedure for transferring data in television lines - Google Patents

Abstract

Special data blocks or parts of data blocks are transmitted in redundant intervals or a heading is transmitted before the corresponding data block, after a suitable time interval, and another data block is inserted. By setting suitable bit errors or a parallel mode bit, premature interruption of data reeipt of the decoder is avoided. During transmission, teletext standared control bit for separating the type of magazine transmission is transmitted with the parallel mode code word.

Description

1,108,385

Method for transmitting data on television lines - Förfarande för överforing ay data i televisionslinjer

The present invention relates to a method for transmitting alphanumeric data according to the preamble of claim 1. Such a method is known from 5 DE 34 18 068.

In Germany, United Kingdom and other European countries, alphanumeric data encoded according to teletext standards (teletext standards) used or proposed by television broadcasters, such as the so-called "Level-1-Teletext" standard, is transmitted periodically or pseudo-periodically by vertical TV signal shutdown. The transmitted data is compiled on the playback side and displayed on a page as a permanent television image (teletext page). The payload data representing each page is assembled into a block preceded by a header data packet identifying the page number of that block.

DE 34 18 068 C1 is arranged such that each header line 15 is preceded by a second data packet (preamble line) of one television line length, whereby this forward line identifies the next page closest in the next transmission period. The variation of this patent may also be arranged to broadcast a pre-line of one television line within the line of the television semi-picture just before the end of the block to be transmitted, and to immediately repeat the header line of the block to be transmitted. Such a repeated title line is also called a subtitle line.

On the playback side, the data is collected in a known decoder (published by the company "Valvo Technische Informationen fur di Industrie", No. TI 840314) in a paging device having a memory capacity of up to four or eight pages of data. Due to the "adaptive transmission principle", this memory space constraint forces the memory to be cleared before displaying a user-selected page * 1! '. Before the data of the selected page - as soon as it appears in the transmission period - can be written down. "Adaptive Broadcasting Principle" means that no :: blank ("blank") teletext line is transmitted in order to shorten the transmission:: 30 transmission periods. In this case, the clearing occurs only after the title bar of the selected page has been decoded.

:. Since quite a number of text-to-speech decoders used so far in television receivers, this erasure takes about 20 ms, so for compatibility reasons, there must be a waiting period of about 20 ms between the transmission of the header line and the subsequent transmission of data. The same applies if, when you re-select a page, the header line contains a special clear command, which occurs, for example, for so-called multiple pages in a transmission period (several different pages having the same page number). To account for such a waiting period, the header line and the subsequent payload data are transmitted in different television half-images.

If possible, in the television semi-picture where the title bar is transmitted, other teletext bars are filled by repeating the title bar. However, this repetition of the header line occurs at the expense of a longer period. Because using multiple page paging memory and full channel use with adaptive paging, a 20 msec clearing period for clearing the entire paging memory is either too short or non-existent, in these cases, you should avoid clearing the entire paged memory in this step.

Furthermore, it is known from EP 0 343 740 A2 to deposit a common identifier for all the lines and header lines on the same page. If the page changes due to the transmission of a new header bar, then each bar on the new page is assigned a new value corresponding to the new header bar ID. When read out, the decoder compares the values of the different lines and reads out the line only when the values are equal; when values are different, blank characters are read for that line.

: It is also known from this patent publication to extend each page with additional drinks # 26-31 ("ghost streaks") to send additional information, such as new characters or commercial information, which, however, represents an extension of the sequence, *: · 25 since nothing changes when repeating the title bars. Also for these ghost lines · *; *; storing an identifier that is not altered by the header line for non-page ghost lines # 29-31.

Finally, DE 39 14 697 A1 is known in connection with teletext to transmit special characters, subtle structures, and color tones on a companion page with a "text line" (Level 1) in accordance with the existing teletext standard. On the receiving side, the desired teletext page (s) (t) Stored separately from the teletext page (s) in question and processed so that those character positions which do not have:.: any supplement data, the characters associated with the basic data can be displayed. 3 '0 8 3 8b associated characters in interaction with the supplement data When transmitting the supplement data in addition to the standard teletext pages (Level 1), the length of the episode increases with the number and length of the supplement pages.

When usually in the television image in which the title lines are transmitted, any other 5 text lines are filled by repeating the title line, according to DE 34 18 068 C1, the redundant title lines are omitted and a second data packet (pre-title line) is inserted before each title line, which indicates the page number of the next page in the transmission cycle. Further, according to this patent, it is arranged that the page-10 memory is already cleared during the transmission of the page preceding the desired page, so that repetition of the header lines can be avoided even taking into account the required clearing times. Thus, according to this method, the length of the period and thus the average wait time of a given page can be drastically reduced.

In practice, however, problems have been encountered in implementing the known header stripe method known from DE 34 18 068 C1, which has resulted in such transmissions being stopped.

For a better understanding of the teletext transmission method, reference is made to "Technische Richtlinie ARD / ZDF, No. 8 R 4, Fernsehtext-Specifikation", Jul-20 by the IRT Institut fiir Rundfunktechnik GmbH, Munich, June 1986. According to this, up to eight magazines are arranged. the numbers below are symbolically represented by the letter "m" (m = 1, 2, ..., 8), to which teletext pages can be linked. Each magazine can contain up to 100 pages, each of which is symbolically represented by "n" ··· 25 (n = 00, 01, 02, ..., 99). Thus, a full teletext page may be assigned to · ··· by a three-digit decimal number (m, n), with the first digit * denoting the magazine, and the second and third digits denoting the page number in this magazine. For example, teletext page 103 corresponds to magazine number 1 «* ;; * page number 03. For teletext service expansion steps, provision is made for \ * 30 expansion in hexadecimal numbers.

, ·, Difficulties encountered in the header line method may be primarily due to the fact that asynchronous calling of an arbitrary page, depending on the internal control processes of the teletext decoder used, may result in this page not being read • or not read at all.

4, 108385

The latter can occur, for example, when the desired teletext page (m, (n + l)) is called on the receiving side before the associated header header (m, (n + l)) VK is received which contains the same information as the header header associated with this page (m (n + l)) Q. According to 5 known methods relating to the header line (m, (n + 1)) VK, the header line (m, n) K follows, which in connection with said internal control process of the teletext encoder, is immediately interpreted to terminate the data teletext section page (m, n + 1) that receiving the header line (m, (n + 1)) K after the teletext page (m, n) has finished transmitting, no longer opens the decoder to recover the page (m, (n + 1)) data.

10 After all, the page (m, (n + l)) is now "received" and no longer needs to be read.

If there is still an intermediate header line (m, n) ZK between the header line (m, (n + 1)) VK and the header line (m, n) K, which contains other transmission line data lines associated with the teletext page (m, n), then for the same reasons, the page (m, n) is only stored incompletely.

In particular, when requesting pages that contain important information for internal decoding and sorting and / or management instructions, such as system tables known as "TOP" (= DE 36 34 757 Cl), this can lead to significant problems. , aside from entirely optical inconsistencies, where missing lines can otherwise also affect "normal" teletext pages.

; It is an object of the invention to implement the method mentioned above without disturbing conventional Level-1 teletext decoders.

According to the invention, this task is solved by the features set forth in claim 1, also in claim 5 and claim 10.

The advantage of the first embodiment of the method according to claim 1 of the method according to the invention is that the transmission of the above header and subtitle strips as described above can be omitted without increasing the length of the sequence, and not only that the shortening of the length of the sequence associated with the header heading method can be utilized and that, in addition to this, a further shortening of the length of the length of the sequence is achieved.

The first embodiment of the invention is based on the observation that,. . the teletext decoder is used in so-called parallel mode so that receiving the header lines after receiving the header bar does not yet stop the data recovery.

5, 108385

In a variation of the method of the invention, when transmitting teletext data to distinguish between magazine types - serial or parallel magazine transmission - the control bit C1I associated with the teletext standard is transmitted with the same value indicating the parallel mode. According to the above-mentioned ARD-ZDF specification, the control bit Cl1 is set to "zero" for this purpose.

This has the additional advantage that the period length reduction associated with the principle of the preamble stripe method can also be utilized in a compatible manner in conventional teletext decoders which require about 20 ms for the initial clearing.

10 The mode of use "parallel form" was once included in the ARD / ZDF specification for a completely different purpose. By attaching the pre-magazines to a particular line or group of lines, several independent transmission sequences can be formed within the vertical shutdown jub of television images. However, depending on the number of pages used, there should be 15 different page access times for different transmission periods within different transmission periods.

Said variation is based on the finding that the control devices of existing teletext encoders are being utilized in such a way that reception of the header bands does not yet stop the data recovery. Namely, if the decoder is informed by the received control bits in question that the "parallel mode" operating mode is available, then on the decoders side, data recovery is only terminated when the header bar denoting the required page is received. , the header of the same magazine is re-received.

• * 4 With this observation, all decoders on the market that ♦ have sufficient ARD / ZDF specifications, such as V · 25 with known teletext processors known as "TPU 2732" and "TPU 2735" by ITT Semiconductors the readiness to retrieve the desired teletext page data requested by the user - * · * ·; y; automatically from the title bar until other header lines belonging to the same magazine are • correctly received.

In another embodiment of claim 5, the method of the invention has the advantage that the length of the sequence,. making the shortening usable in a compatible manner.

6, 108385

Another embodiment of the invention is based on the finding that teletext decoder control devices are operated such that after receiving the header or sub-header, the subsequent receiving of the header, header or sub-header does not yet complete data recovery.

5 On the basis of this observation, for example, an error detection device for such control purposes can be used in connection with the teletext processors known as "TPU 2732" and "TPU 2735", already known as ITT Semiconductors. Namely, if the error detection device detects a bit error when receiving teletext pages, then an error flag 10 (eror flag) is raised for the internal control process. It follows that a teletext page marked in this way will be reloaded as soon as it is received again in the episode. Thus, it is now sufficient that all the header lines are transmitted on the transmitter side suitably with at least one bit error, so that the teletext decoder is controlled according to all artistic rules so that the subsequent reception of the header, header, or subtitle lines does not stop data recovery. If subtitle lines are provided in the transmission period, these are also transmitted in the same desirable way as incorrect. Since errors may occur in the transmission distance between the transmitter and the receiver, which may deliberately override the bit errors made in the transmitter, the variant of the invention is arranged so that most or even all data with parity assurance identify errors with greater probability. In addition, it may be arranged that the data to be verified by the Hamming code is not transmitted without errors in the transmitter to ensure that this data is more likely to remain recoverable on the decoder side, even if errors occur during transmission.

«« I «* *« * »

According to the third embodiment of claim 10, the method according to the invention has the advantage that the alphanumeric data signals are transmitted such that the supplement pages for higher teletext levels (Level) do not load or lightly load the entire sequence.

A preferred embodiment of the method of receiving data transmitted in accordance with the invention is set forth in claim 11.

7 108385

According to a third embodiment of the method according to the invention, the transmission capacity lost by repeating the header lines is utilized in the prior art for transmitting supplement pages.

Other features, advantages and details of the invention will now be explained in more detail by means of embodiments with reference to the drawing. In this case: Figure 1a is a schematic representation of a section of teletext pages according to the state of the art using prefix lines; Fig. Ib is a schematic representation of a section of teletext pages illustrating an embodiment of a first embodiment of a transmission method according to the invention; Fig. 2a is a schematic representation of a portion of the prior art teletext lines, but without the preamble strip method; Fig. 2b is a diagrammatic representation of a portion of a prior art teletext line segment using preamble and subtitle lines; Figures 3a, b are schematic portions of a section of teletext lines according to a first embodiment of a third embodiment of the transmission method (Fig. 3b) of the invention compared to the prior art (3b); and FIG. 3c is a schematic representation, as in FIG. 3b, but according to a second embodiment of the third embodiment of the transmission method (FIG. 3b) of the invention.

In Figure 1a, the transmission section of teletext pages schematically includes blocks 100, -102, 103, 205, 210, 300, 505, and 520, preceded by headers 100K, 102K, ..., 520K, respectively. Before each such header line, a forward header line 102VK, 103VK, ..., 100VK indicating the next block is always transmitted. Ku ·· '- in Figure la otsikkojuovaa 520K and a block 520 pre-esiotsikkojuova 100VK take ... "25 account the fact that after sending the 520 block transmission period is repeated, •» * *, such as the arrow P1 has been shown.

• I · <* 'y, The payload data for each of these blocks together represents one teletext page. The number of this • • * teletext page is indicated by the associated title bar (m, n) K.

«· ·:: '; 30 By means of the header line (m, n) K, the decoder on the receiver side is already received. at the beginning of the transmission of a wu or block, i.e. "temporarily", information about which page is to be transmitted next, so that when the user selects the page number (m, n) of this next page, the immediately preceding page ((ml), (nl)) clearing the decoder side memory. When the title bar of the desired page (m, n) 8 108385 (m, n) K occurs, the empty page memory can then immediately receive the incoming payload data for this page.

Usually, only a limited transmission area is available for transmitting teletext data in the vertical shutdown interval of each television half image, for example, 5 may comprise five television lines. In an extreme case, all lines of the television half-image can also be used for this purpose, for example in connection with the so-called teletext channel of cable television.

Due to the long waiting period of about 20 ms described at the outset, according to the state of the art, a uniform minimum interval of approximately 20 ms must be maintained between each header header and the first 10 payload lines of each block thereof.

The headers and subheads according to the known method described so far do not differ in any way from their associated headers - regardless of their position in the teletext data period. Therefore, the use of this method also resulted in incorrect reproduction of teletext pages on many teletext decoders. The decoders in question had, upon receiving the subtitle or header lines indicated by the header lines, resulted in the appearance of a new text television page. The decoder control interprets a page that has already begun and is now in continuous reading, or only 20 pages that are actually being read in, already finished.

By means of similar suitable control devices, such as "TPU 2732" and "TPU 2735" by the ITT Semiconductors with known teletext processors, the teletext decoder according to the invention can be controlled from the ·· transmission side without interpreting data recovery as unwanted. These and all others that comply with said ARD / ZDF specification • · i. i. The control bit recognition device provided with the decoders can be used * ·· '. for such control purposes.

«« ·

Namely, when receiving a teletext page from the transmitter side '**, the control bit set to "zero", respectively, is recognized by the decoder as having "parallel mode" operation, then the decoder stops data recovery. Only when the header line of the same magazine is re-received after receiving the header line denoting the requested page.

The block 100, 205,102, 210,103, 505, 300, and 520 of the blocks 100, 205,102, 210,103, 505, 300, and 520 described in FIG. 1, schematically illustrated in FIG. 1b, according to an exemplary embodiment of the first embodiment of the method of the invention, are preceded by header lines 100K, 205K, ..., 520K. However, according to the method shown in Figure 2, the transmitted header lines are connected to the teletext data stream in such a way that the minimum distance required to clear the page memory reserved for data retention is maintained between each header line and its associated block, e.g.

In the representation of Fig. Ib, the pre-header line 100K preceding block 520 takes into account that after transmission of block 520, the transmission period is repeated by transmitting the ot-10 pig line 205K, block 100, etc., as indicated by arrow P2.

The prior art headers required so far in the transmission method described in Fig. Ib may be omitted, thereby providing, in addition to being compatible with the decoders available on the market, the additional advantage that the length of the sequence is further reduced compared to the prior art.

The portion of the prior art teletext line segment shown in Fig. 2a includes blocks 10, 20 and (partially) 30, each containing a preceding header line K and subsequent variable length payload lines 1, 2, 3, 4, .... Each block 10, 20 , 30 payloads represent teletext pages. The number of the 20 teletext pages in question is identified by the associated title line K. In the example shown, it is assumed that a transmission area A1, A2, or A3, ..., respectively, with five television lines for teletext data is available in the vertical shutdown interval of each television half image. In the extreme case, all the lines in the • • i television semi-picture may be available for this purpose, for example in connection with the so-called teletext channel of cable television.

• * »• * '1 *. Due to the waiting period of about 20 ms described initially in the transmission areas A2 and A5]! ! * is a teletext standard to repeat the title line K once (A2) or four • · * times (A5) to maintain the required time span between the title line and the next payload line 1.

· »·:: ': 30 To avoid this, cf. Fig. 2b, according to the so-called header header method. A forward header line VK is transmitted before the header line K, which indicates the page number of the next page of the transmission period. In the case of block 20 ', the header header VK indicates the number of the page 102 to be transmitted in the subsequent block 30'. By means of the header line VK, the receiver-side decoder already receives a page or 10 '083c' block at the beginning of transmission or "temporarily" which page is to be transmitted next, so that when the user selects the page number of this next page clearing the decoder page memory. When the title bar of the desired page appears, the empty page memory 5 can then immediately receive the incoming payload data for this page.

In the case of block 20 ', its block end is in the transmission area A5. The header header VK with the numbers on the next page 102 is therefore transmitted in the transmission area A4, whereby the position of the header header VK in the transmission area A4 can be freely selected.

After transmitting the header line VK after the page has been transmitted to identify the payload line 10 of the block 20 'after it which has not yet been fully transmitted by the decoder, the header line K of the currently transmitted block is immediately repeated as the header line ZK.

The headers and subheaders according to the known method described so far do not differ in any way from their associated headers - apart from their position in the teletext data period. Therefore, the use of this method also resulted in the incorrect reproduction of teletext pages in many teletext decoders. The decoders in question had received a new teletext page when receiving the subtitle lines or header lines indicated by the header lines. The decoder control interprets a page that has already begun and is now in continuous reading, or only a page that is actually being read, already finished.

Corresponding suitable control devices, such as ITT Semiconductors', with the type designations "TPU 2732" and "TPU 2735" are known teletext processes. According to an embodiment of the second embodiment of the transmission method 25 of the invention, the teletext decoder may be controlled from the transmission side si-L .., so that it does not interpret the data recovery as terminated in an undesirable manner. For example, the error detector provided with such processors may be used for such control purposes. Namely, if a bit error is detected by an error detector when receiving teletext pages, then an error flag is set for the si-30 control process. As a result, the teletext page marked in this way will be reloaded as soon as it is received again in the episode.

Thus, for example, if all the header headers are each transmitted with one bit error, then the processor control interprets the data recovery 35 as not yet completed, so that the subsequent receipt of the header, header, or subhead 10 8 3 8 5 strips does not stop the data recovery. If there is now an associated header or sub-header after receiving an invalid header heading, then read-only memory can be started or resumed immediately. If subtitle lines are provided in the transmission period, these 5 are also transmitted in the desired manner in the wrong way.

Figure 3a below shows, for comparison purposes, a portion of a known teletext transmission line transmission period. The known section contains blocks 10 and (partially) 20 containing preceding header line K and subsequent variable length payload lines 1, 2, 3, 4, .... The payload data of each block 10, 20, 30 each represent 10 teletext pages. The number of the teletext page in question is identified by the associated title bar K. In the example shown in Figure 3a, it is assumed that a transmission area A1 ', A2' or A3 ', ..., respectively, with seven television lines for transmitting teletext data is available in the vertical shutdown interval of each television half image. In the extreme case, all the lines in the television half-image may also be available for this purpose.

Due to the waiting period of about 20 ms at the beginning, according to the prior art, the header line K should be repeated five times (in Al ') or four times (in A3') in the transmission areas AI'and A3 'to maintain the required 1 between.

In the first embodiment of the third embodiment of the transmission method according to the invention shown in Fig. 3b, the television lines are not filled with header; by repeating lines K, but they are used to send supplement pages. In the case of block · 10 ', five free lines of block K100 are used to transmit block. j * 25 formed by the title line K10A of the fill page 10A and the payload lines 1-4. The other payload lines 5-7 of the replenishment page 10A are transmitted in block 31 instead of repeating the header line K101.

4 *

As can be seen by comparing the blocks 10, 20 and 10 ', 20' in Figures 3a and 3b respectively, by not repeating the header lines, the benefit of data transmission capacitance is eliminated. As practice measurements have shown, repeating headline beverages will lose about 12% of the available data capacity when the bar number is seven lines per half image, and these can be utilized in transmitting supplement pages according to the invention. At 08385 per eleven, 30% of otherwise unused transmission capacity is already available for refill pages.

The conventional receiving-side decoder (Level 1) is not interfered with by the exhilarating transmission method, since a waiting time of about 20 ms is maintained for all conventional teletext pages. In contrast, the wait interval does not need to be maintained for refill pages, as these refill pages are interpreted by new designable higher level decoders using a faster internal flush method. In such cases, such new decoders identify a special data block by means of a specific social drink which has been decoded earlier than received. The identified special data block is stored as or as part of a special teletext page or as a queue of special teletext pages for further processing.

If the available transmission capacity is not sufficient for the refill pages, another embodiment of the third embodiment of the transmission method of the invention shown in Figure 3c suggests that instead of repeating the header lines, to be sent without regard to waiting periods. In addition to the refill pages, the number of extinguishing areas it occupies and the resulting period length is obtained from the data amount of full-20 ness pages transmitted in the same period. As shown in Fig. 3c, the supplement page 10A, which according to Fig. 3b consists of blocks 30 and 31, by means of which the normal teletext page 100 (block 10 ') is not transmitted in truncated form, but as a solid block 30'. The capacity remaining in the extinction area A2 'is used to send the second Supplement V page 10B (block 40). The page 100 (block 10 ") is delayed accordingly.

In the embodiment of this embodiment, it is to be assumed that, for example, when transmitting a filler page, t f «, the length of the episode for each of the three teletext pages (Level 1) does not increase by 30% but only about 10%.

e i * »« »t« t a «· I!

Claims (11)

13 108385 A method for transmitting coded alphanumeric data in a cyclic or quasi-pulse mode on a television strip which is compiled on the playback side and displayed as a stationary television image (teletext page), wherein at least two teletext pages are arranged (line), preceded by a single television line data packet (header line) denoting the magazine and page number of this block, characterized in that each data packet of each block carries the magazine number associated with this block-10, that not all teletext pages are inserting a second block (103) and / or a second header line (300K) between each block (505) and its associated header line (505K), wherein the second block (103) contains only such data packets associated with the same text-broadcast page (03) and having the same magazine number (1) different from the magazine number (5) of the first block (505), and wherein the data packet containing the second header line (300K) has a magazine number (3) which differs from the magazine number (5) of the first header line (505). A method according to claim 1, characterized in that, when transmitting teletext pages, a control bit having a value indicating a parallel form arranged to separate the magazine broadcast types is transmitted at the same time. Method according to claim 1 or 2, characterized in that, on the one hand, the data packets of each block and, on the other hand, the header lines attached thereto are transmitted in lines of different television half-images. • ««. • · *, * · '. 25 Method according to one of the preceding claims, characterized in that y. '. a minimum spacing of about 20 ms is maintained between each header line data packet and the associated block data packets * «t. The method and / or method according to any one of the preceding claims: 'I': for cyclic or pseudoranged transmission of encoded alphanumeric data on 30 television lines which are compiled on the playback side and displayed as a stationary television image, each payload representing one page being compiled into a block a first television line data packet (header line) indicating a page number, and wherein a second single TV line data packet (header line) indicating a page number of the next page in the 14 108385 transmission sequence, preceding at least one header line with at least one header header data . A method according to claim 5, characterized in that the header lines of the block to be transmitted are transmitted repeatedly (as header lines), and that at least one parity error is included in the data of each header line on the transmitter side. 7. A method according to claim 5 or 6, characterized in that on the transmitter side of the data of the header lines and possibly the data of the header lines only such data contains a parity error, which data is provided with a parity check against the transmission standard used. A method according to claim 7, characterized in that on the transmitter side of the data of the header lines and possibly the data of the header lines, all such data has a parity error, which data is provided with a parity check according to the transmission standard used. Method according to one of the preceding claims 6 to 8, characterized in that on the transmitter side the data of the header lines and / or possibly the data of the header lines lack any parity error, which data is provided with a Hamming code according to the transmission standard used. A method and / or method for the cyclical or pseudoranged transmission of encoded alphanumeric data according to any one of the preceding claims:; . television lines, which on the playback side are assembled and displayed as a stationary television image (teletext page), whereby payload data representing each page is assembled into a block preceded by a single page data packet (header line) and a header line followed by a header line; ;; there is a wait period »♦« * · * * between the payload line of the teletext page associated with the title line, whereby one or more, '· * amp special data blocks may be transmitted between the last payload line of the teletext page and the next teletext page header line. ::: 30-turn television image blanking areas, characterized in that the title line (K100) of the next teletext page (cf. block 10 ') is not repeated in the section, and that the special data block (s) (30, 31) portions of the payload teletext pages identified by the special header line (K10A) transmitted prior to said special data block (30, 31), which for the 1 08385 created the special teletext page, does not follow the wait period between the special header line and the next special benefit page. A method for receiving encoded alphanumeric data contained in transmitted television bands according to claim 10, characterized in that the special data block is identified by a dedicated, received and decoded special header line and stored as a special teletext page or a series of special teletext pages.