Television – Nonpictorial data packet in television format – Including teletext decoder or display
Reexamination Certificate
1999-12-03
2001-05-29
Eisenzopf, Reinhard J. (Department: 2614)
Television
Nonpictorial data packet in television format
Including teletext decoder or display
C348S461000, C348S465000, C348S467000, C348S473000, C348S474000, C348S478000
Reexamination Certificate
active
06239844
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a television receiver for receiving a television signal having a data signal associated therewith, said data signal representing pages of text and/or graphics.
2. Description of the Related Art
Such television receivers are well known in which the data signal associated with the television signal is a teletext signal. The teletext signal is multiplexed with the television signal by transmitting it during the vertical blanking interval of a standard analog television signal. The television receiver then includes a teletext decoder which is able to acquire the data signals transmitted in the vertical blanking interval, and store and display one or more pages of the information represented by the teletext data signal. Teletext decoders have become increasingly complex in order to offer additional features, such as FASTEXT, TOP, EPG, Favorite Pages etc. and are normally controlled by a microcontroller which, in order to allow the additional features to be selected and displayed, has increasing amounts of software stored in programme memory associated with the microcontroller. As further features are added the re-writing of this software is an increasingly arduous task. In addition, a series of different teletext decoders which differ in the number of features provided, comprise basically the same hardware, that is microcontroller, data acquisition circuit, and display circuits, but have varying amounts of associated memory for storing the received data and differing programme memory to enable either only basic functions to be performed or allowing more complex additional features to be provided.
One of the known problems with the teletext system is the time taken after a request by a viewer to acquire a particular page of information. This arises because the pages are sent serially and there is a cycle time of the order of 30 seconds for all the data to be transmitted. It is, of course, impossible to acquire and store data apart from when the page is transmitted in the cycle. One way of overcoming this disadvantage is to provide a large amount of data storage in the television receiver so that all pages of a cycle may be acquired in the background and, when the user wishes to view a teletext page, it will then already be stored in the memory. This however, does require a large memory particularly when allowance has to be made for rotating pages as well as the normal magazine pages.
A number of schemes have been devised for anticipating which pages a viewer is likely to wish to access and to give priority to the acquisition and storage of those pages. Examples are the FASTEXT system and the TOP system. In these systems, pages are grouped according to the broadcaster's anticipation of which pages are likely to be of interest to a viewer who has accessed a particular page. With the FASTEXT system, the numbers of the pages which are linked to the page currently selected are sent in extension packets or ghost rows of the teletext signal. The microcontroller then decodes these additional page links and instructs the acquisition circuit to acquire those pages. In the TOP system a different approach is adopted in that a special page, called the Table of Pages is transmitted which indicates those pages which are in the transmission cycle and the way in which they are grouped. Thus, when a particular page is selected, the microcontroller will access the Table of Pages and determine from the Table which further pages should be acquired as being likely to be of interest to a viewer who has selected the page in question.
Further, television receivers are known in which the habits of the viewer are monitored and a list of habitually accessed pages is constructed and stored in memory. These pages are then acquired as soon as the receiver is switched on, or when the received channel is changed, as being the pages most likely to be accessed by the viewer. In this case, the habitually accessed or Favorite Pages will be stored in a portion of the memory associated with the teletext decoder. Thus, provided a minimum time elapses between activating the receiver or changing channel and the viewer deciding to attempt to access teletext pages, then those particular pages will already be available when the viewer requests them and it will not be necessary to wait for them to reappear in the transmission cycle before being able to display them.
A number of other services are also being introduced, such as electronic program guide (EPG), and it is becoming increasingly difficult to determine which pages should be acquired by the data acquisition circuit and stored in memory in order to enable the viewer to have the fastest access to the information.
SUMMARY OF THE INVENTION
It is an object of the invention to enable the provision of a television receiver in which teletext or other data signals may be acquired and stored in an efficient manner so that the viewer is able to access pages of information without unacceptable delay.
The invention provides a television receiver for receiving a television signal having a data signal associated therewith, said data signal representing pages of text and/or graphics, a page being displayable in place of or superimposed on a television picture, said television receiver including means for acquiring at least requested pages of said data, a page memory having a plurality of locations for storing requested pages of said data, and means for generating an ordered queue of locations within the page memory for storing the requested pages; wherein said generating means comprises a plurality of page request generators, each page request generator being arranged to receive requests from a different source or for a different purpose for pages having selected addresses to be stored and producing in response to the received requests an ordered priority list of addresses of pages requested to be stored in the page memory, priority setting means coupled to each of the page request generators for allocating priority between the page requests of the lists of page requests of each of the page request generators, the priority setting means being arranged to produce therefrom the ordered queue of page requests and to cause said queue to be updated when any of the page request means receives a page request and updates its own priority list in response thereto.
By this means, the capacity of the page memory may be efficiently utilized so that the pages most likely to be accessed by a viewer are pre-captured and stored in the page memory and are consequently available for display with a minimum of delay.
The page request generators, which may be computer programs controlling the microcontroller which controls the data acquisition and storage, each deal with a specific class of requests. Thus, there is a display page request generator which reacts to the request by the user using a remote control unit (RCU) for a particular page to be acquired and displayed. Thus, the microcontroller will monitor page requests made by a viewer using an RCU, and when one is received, will cause the display page request generator to determine the priority within that class of page requests and to request a place in a priority queue from the priority setting means. A further page request means may control the microcontroller so that it causes the data acquisition circuit to acquire all the favorite pages of the viewer and to store them in the page memory. A further page request means may react to data which is contained in the teletext signal. Thus, for example, when FASTEXT page links are being transmitted, then when a page is acquired, there are a number of extension packets which specify the pages which are linked to the acquired page. Thus, a page request generator will use the information relating to the linked pages to cause an ordered list of those particular linked pages to be produced and requested from the priority setting means. Similarly, with the TOP system, the page request means for the TOP data will request the p
Eisenzopf Reinhard J.
Goodman Edward W.
U.S. Philips Corporation
Yenke Brian P.
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