Rapid access teletext decoder arrangement

Claim 2

A television apparatus responsive to an incoming television signal containing video lines that carry text data, defining corresponding data lines, for generating an output signal that is capable of providing picture information to a display device, comprising: means for generating a first control signal in order to select one of said data lines to be used in conjunction with the generation of said output signal; a source of said television signal; characterized by a first-in, first-out background memory (45) having a data input that is coupled to an output of said source; first control means (55) coupled to said background memory (45) for controlling storage therein of corresponding data lines of said television signal (VIDEO), wherein prior to the time said first control signal is generated, said background memory already contains a substantial number of stored data lines of said television signal; second control means (50) responsive to said first control signal and coupled to said background memory (45) for controlling during a given interval that follows the generation of said first control signal, read-out from said background memory (45) of a plurality of data lines of said television signal that have been stored before the end of said given interval, said given interval having a duration that is substantially shorter than that of a corresponding interval between the occurrence of an initial data line of said plurality of data lines and the occurrence of a final data line thereof so as to reduce access time to said plurality of data lines, said second control means (50) controlling read-out of said plurality of data lines in a first-in, first-out manner for generating, during said given interval, a data signal (TTDin) that contains the data of said plurality of data lines including data lines that have been stored in said background memory (45) during said given interval; and a data processor (30) responsive to said data signal (TTDin) for selecting said one data line to generate in accordance therewith said output signal (R,G,B).

Claim 3

An apparatus according to Claim 1 characterized by means (80) for coupling said data signal (TTDin) and said television signal (TTDout) to said data processor (30) such that prior to the time said first control signal is generated said television signal (TTDout) is coupled to said data processor (30) in a manner that bypasses said background memory (45).

Claim 4

An apparatus according to Claim 2 characterized in that throughout said given interval, said coupling means (80) decouples said signal (TTDout) that bypasses said background memory (45) from said data processor (30).

Claim 5

An apparatus according to Claim 1 characterized by a switch (80) having a first input (A) that is coupled between said output of said source of said television signal and said data input of said background memory (45), a second input (B) that is coupled to a data output (45b) of said background memory (45) and a switch output (80a) that is coupled to an input of said data processor (30).

Claim 6

An apparatus according to Claim 4 characterized by means (100) for generating a second control signal (FLAG) that is coupled to a control input (C) of said switch (80), said second control signal having a first state for enabling said switch (80) to couple the signal that is developed at said second input (B) of said switch (80) to said data processor (30) following the time when said first control signal (from 65) is generated and having a second state, for enabling said switch (80) to couple the signal that is developed at said first input (A) thereof to said data processor (30) following the occurrence of the earlier of (a) a time when all the data stored in said background memory (45) has been read out, and (b) a time when a first time-out interval has elapsed from a time when said data processor (30) selects the data of said first data line that is a Page Header data line.

Claim 7

An apparatus according to Claim 4 characterized by means (75) coupled to said background memory (45), for generating, in accordance with the data of said plurality of data lines, a serial bit data signal (TTDin) that contains corresponding data lines that are read out of said background memory (45) in a first-in, first-out manner, said serial bit data signal (TTDin) being coupled to said second input (B) of said switch (80), said switch coupling said serial bit data signal (TTDin) to said input of said data processor (30), during said given interval, and coupling the signal that is developed at said first input (A) of said switch (80) to said input of said data processor (30), outside said given interval.

Claim 8

An apparatus according to Claim 1 characterized by a switch (80) for coupling one of said data signal (TTDin) that is generated at an output of said background memory (75) and a second data signal (TTDout), that bypasses said background memory (45), to an input of said data processor (30) when a second control signal that is developed at a control input (C) of said switch (80) is at first state and for coupling the other one of said first and second data signals to said input of said data processor (30) when said second control signal is at a second state.

Claim 9

A television apparatus according to Claim 1 characterized by a page memory (70) responsive to said output signal for storing said output signal therein.

Claim 10

A television apparatus responsive to an incoming television signal containing video line signals that carry text data, defining corresponding data lines, for generating an output signal that is capable of providing picture information to a display device, characterized by means (65) for generating a first control signal in order to select one of said data lines to be used in conjunction with the generation of said output signal; a source (20) of said television signal; a first-in, first-out background memory (45) having a data input that is coupled to said source (20); first control means (55) coupled to said background memory (45) for controlling storage therein of corresponding data lines of said television signal, wherein prior to the time said first control signal is generated, said background memory (45) already contains a substantial number of stored data lines of said television signal; second control means (50) responsive to said first control signal and coupled to said background memory (45) for controlling during a given interval that follows the generation of said first control signal, read-out from said background memory (45) of a plurality of stored data lines of said television signal, such that the duration of said given interval is substantially shorter than that of a corresponding interval between the occurrence of an initial data line of said plurality of data lines and the occurrence of a final data line thereof, so as to reduce access time to said plurality of data lines, said second control means (50) controlling read-out of said plurality of data lines in a first-in, first-out manner for generating during said given interval a data signal that contains the data of said plurality of data lines; a switch (80) having a first input (A) that is coupled to said source (20) of said television signal, having a second input (B) that is coupled to a data output of said background memory (45) and having an output (80a) for generating a second data signal; a data processor (30) responsive to said second data signal for selecting said one data line to generate in accordance therewith said output signal; and means (100) for generating a second control signal that is coupled to a control input (C) of said switch (80), said second control signal having a first state for enabling said switch (80) to couple, to said data processor (30) after said first control signal is generated, the signal that is developed at said switch second input (B), and having a second state for enabling said switch (80) to couple to said data processor (30) the signal that is developed at said first switch input (A) following the occurrence of the earlier of (a) a time when all the data stored in said background memory (45) has been read out, and (b) a time when a time-out interval has elapsed from a time when said data processor (30) selects said one data line that is a Page Header.

Claim 11

A television apparatus responsive to an incoming television signal containing video line signals that carry text data, defining corresponding data lines, for generating an output signal that is capable of providing picture information to a display device, characterized by means (65) for generating a first control signal in order to select one of said data lines to be used in conjunction with the generation of said output signal; a source (20) of said television signal; a first-in, first-out background memory (45) having a data input that is coupled to said source (20); first control means (55) coupled to said background memory (45) for controlling storage therein of corresponding data lines of said television signal, wherein prior to the time said first control signal is generated, said background memory (45) already contains a substantial number of stored data lines of said television signal; second control means (50) responsive to said first control signal and coupled to said background memory (45) for controlling during a given interval that follows the generation of said first control signal, read-out from said background memory (45) of a plurality of stored data lines of said television signal, such that the duration of said given interval is substantially shorter than that of a corresponding interval between the occurrence of an initial data line of said plurality of data lines and the occurrence of a final data line thereof, so as to reduce access time to said plurality of data lines, said second control means (50) controlling read-out of said plurality of data lines in a first-in, first-out manner for generating during said given interval a data signal that contains the data of said plurality of data lines; a switch (80) having a first input (A) that is coupled to said source (20) of said television signal, having a second input (B) that is coupled to a data output of said background memory (45) and having an output (80a) for generating a second data signal; a data processor (30) responsive to said second data signal for selecting said one data line to generate in accordance therewith said output signal; and means (100) for generating a second control signal that is coupled to a control input (C) of said switch (80), said second control signal having a first state for enabling said switch (80) to couple, to said data processor (30) after said first control signal is generated, the signal that is developed at said switch second input (B), and having a second state for enabling said switch (80) to couple to said data processor (30) the signal that is developed at said first switch input (A) following the occurrence of the earlier of (a) a time when all the data stored in said background memory (45) has been read out, and (b) a time when a time-out interval has elapsed from a time when said data processor (30) selects said one data line that is a Page Header.

Claim 12

A television apparatus responsive to an incoming television signal containing video lines that carry text data, defining corresponding data lines, for generating an output signal that is capable of providing picture information to a display device, characterized by first means (65) for generating a first control signal in order to select one of said data lines to be used in conjunction with the generation of said output signal (R,G,B); a source (20) of said television signal (VIDEO); a first-in, first-out background memory (45) having a data input that is coupled to said source (20); second means (40) coupled to said background memory (45) and responsive to said television signal (VIDEO) for identifying in a given video line, a data sequence of a clock run-in portion of a data line and for storing in said background memory (45) such video lines that are identified as data lines but only when said data sequence of said clock run-in portion is identified (65), said first means for generating a first control signal storing said data lines such that prior to the generation of said first control signal, said background memory (45) already contains a substantial number of stored data lines of said television signal; third means (50) responsive to said first control signal and coupled to said background memory (45) for controlling during a given interval that follows the generation of said first control signal, read-out from said background memory (45) of a plurality of stored data lines of said television signal, such that the duration of said given interval is substantially shorter than that of a corresponding interval between the occurrence of an initial data line of said plurality of data lines and the occurrence of a final data line thereof, so as to reduce access time to said plurality of data lines, said third means (50) controlling read-out of said plurality of data lines in a first-in, first-out manner for generating during said given interval, a data signal that contains the data of said plurality of data lines; and a data processor (30) responsive to said data signal for selecting said one data line to generate in accordance therewith said output signal.

Claim 13

A television apparatus responsive to an incoming television signal containing video lines that carry text data, defining corresponding data lines, for generating an output signal that is capable of providing picture information to a display device, characterized by first means (65) for generating a first control signal in order to select one of said data lines to be used in conjunction with the generation of said output signal (R,G,B); a source (20) of said television signal (VIDEO); a first-in, first-out background memory (45) having a data input that is coupled to said source (20); second means (40) coupled to said background memory (45) and responsive to said television signal (VIDEO) for identifying in a given video line, a data sequence of a clock run-in portion of a data line and for storing in said background memory (45) such video lines that are identified as data lines but only when said data sequence of said clock run-in portion is identified (65), said first means for generating a first control signal storing said data lines such that prior to the generation of said first control signal, said background memory (45) already contains a substantial number of stored data lines of said television signal; third means (50) responsive to said first control signal and coupled to said background memory (45) for controlling during a given interval that follows the generation of said first control signal, read-out from said background memory (45) of a plurality of stored data lines of said television signal, such that the duration of said given interval is substantially shorter than that of a corresponding interval between the occurrence of an initial data line of said plurality of data lines and the occurrence of a final data line thereof, so as to reduce access time to said plurality of data lines, said third means (50) controlling read-out of said plurality of data lines in a first-in, first-out manner for generating during said given interval, a data signal that contains the data of said plurality of data lines; and a data processor (30) responsive to said data signal for selecting said one data line to generate in accordance therewith said output signal.