Teletext interface for digital storage medium having synthetic video generator

Claim 2

An interface circuit for use with a television receiver and means storing a plurality of digitally encoded signals each representing a selected text/graphics character intended for transmission as a corresponding video signal during the active scanning lines of a standard television signal comprising: means converting each of said digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character; means arranging said teletext encoded signals in a plurality of standard teletext formatted data rows; means inserting in time multiplexed manner each of said teletext formatted data rows in a respective teletext line of said television signal; means amplitude modulating said television signal including said video signal and said teletext lines on a television channel RF carrier; and means for coupling said modulated television signal to the antenna terminals of said television receiver, whereby a television receiver having a built-in teletext type decoder is operable in response to said teletext formatted data rows for displaying said selected text/graphics characters in a relatively high quality form and a standard television receiver is operable in response to the video signal comprising said active scanning lines for displaying said text/graphics characters in a poorer quality form.

Claim 3

Apparatus for use with a television receiver comprising: means storing a plurality of digitally encoded signals each representing a selected text/graphics character; first means converting said digitally encoded signals to a baseband video signal reflecting the corresponding text/graphics characters and comprising a plurality of active horizontal scanning lines of a standard television signal; second means converting each of said digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character; means inserting in a time multiplexed manner said teletext encoded signals as a plurality of teletext formatted data rows in successive teletext lines of said television signal; means amplitude modulating said television signal including said video signal and said teletext lines on a television channel RF carrier; and means for coupling said modulated television signal to the antenna terminals of said television receiver, whereby a television receiver having a built-in teletext type decoder is operable in response to said teletext formatted data rows for displaying said selected text/graphics characters in a relatively high quality form and a standard television receiver is operable in response to the video signal comprising said active horizontal scanning lines for displaying said text/graphics characters in a poorer quality form.

Claim 4

Apparatus for use with a television receiver comprising: means storing a plurality of digitally encoded signals each representing a selected text/graphics character; first means converting said digitally encoded signals to a baseband video signal reflecting the corresponding text/graphics characters and comprising a plurality of active horizontal scanning lines of a standard television signal; second means converting each of said digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character; means inserting in a time multiplexed manner said teletext encoded signals as a plurality of teletext formatted data rows in successive teletext lines of said television signal; means amplitude modulating said television signal including said video signal and said teletext lines on a television channel RF carrier; and means for coupling said modulated television signal to the antenna terminals of said television receiver, whereby a television receiver having a built-in teletext type decoder is operable in response to said teletext formatted data rows for displaying said selected text/graphics characters in a relatively high quality form and a standard television receiver is operable in response to the video signal comprising said active horizontal scanning lines for displaying said text/graphics characters in a poorer quality form.

Claim 5

Apparatus according to claim 2 wherein said second converting means comprises memory means storing a plurality of teletext encoded text/graphics characters at a plurality of respective memory locations, each of said memory locations being addressed by the digitally encoded signal representing the corresponding text/graphics character.

Claim 6

Apparatus according to claim 2 wherein said inserting means comprises means inserting the teletext formated data rows comprising recently changed ones of said teletext encoded signals in said teletext lines on a priority basis in relation to the teletext formated data rows comprising unchanged ones of said teletext encoded signals.

Claim 7

Apparatus according to claim 2 wherein said stored digitally encoded signals are arranged in a plurality of data rows and wherein said inserting means comprises: means comparing the teletext encoded signals corresponding to each data row of said digitally encoded signals with the corresponding data row during successive active scanning intervals of said television signal; and means responsive to said comparing means for inserting the teletext encoded signals corresponding to each data row of said digitally encoded signals resulting in an inequality comparison in a teletext line of said television signal as a teletext formated data row on a priority basis in relation to the teletext encoded signals corresponding to the data rows of said digitally encoded signals resulting in an equality comparison.

Claim 8

Apparatus according to claim 5 wherein said inserting means comprises means for inserting the teletext encoded signals corresponding to each of the data rows of said digitally encoded signals resulting in an equality comparison in a teletext line of said television signal as a teletext formated data row on a sequential basis.

Claim 9

Apparatus for use with a television receiver comprising: means storing a plurality of data rows each comprising a plurality of digitally encoded signals, each of said digitally encoded signals representing a selected text/graphics character; first means converting the digitally encoded signals comprising each of said data rows to a video signal reflecting the corresponding text/graphics characters, each of said video signals comprising a plurality of successive horizontal scanning lines in the active scanning interval of a standard television signal; second means converting the digitally encoded signals comprising each of said data rows to a respective plurality of teletext encoded signals representing the corresponding text/graphics characters; means comparing the teletext encoded signals corresponding to each data row of said digitally encoded signals with the corresponding data row during successive active scanning intervals of said television signal; means responsive to said comparing means for inserting in a time multiplexed manner the teletext encoded signals corresponding to each data row of said digitally encoded signals resulting in an inequality comparison in a teletext line of said television signal as a teletext formatted data row on a priority basis in relation to the teletext encoded signals corresponding to data rows of said digitally encoded signals resulting in an equality comparison; and means amplitude modulating said television signal including said video signal and said teletext lines on a television channel RF carrier.

Claim 10

Apparatus for use with a television receiver comprising: means storing a plurality of data rows each comprising a plurality of digitally encoded signals, each of said digitally encoded signals representing a selected text/graphics character; first means converting the digitally encoded signals comprising each of said data rows to a video signal reflecting the corresponding text/graphics characters, each of said video signals comprising a plurality of successive horizontal scanning lines in the active scanning interval of a standard television signal; second means converting the digitally encoded signals comprising each of said data rows to a respective plurality of teletext encoded signals representing the corresponding text/graphics characters; means comparing the teletext encoded signals corresponding to each data row of said digitally encoded signals with the corresponding data row during successive active scanning intervals of said television signal; means responsive to said comparing means for inserting in a time multiplexed manner the teletext encoded signals corresponding to each data row of said digitally encoded signals resulting in an inequality comparison in a teletext line of said television signal as a teletext formatted data row on a priority basis in relation to the teletext encoded signals corresponding to data rows of said digitally encoded signals resulting in an equality comparison; and means amplitude modulating said television signal including said video signal and said teletext lines on a television channel RF carrier.

Claim 11

Apparatus according to claim 7 wherein said second converting means comprises memory means storing a plurality of teletext encoded text/graphics characters at a plurality of respective memory locations, each of said memory locations being addressed by the digitally encoded signal representing the corresponding text/graphics character.

Claim 12

Apparatus according to claim 7 wherein said inserting means comprises means for inserting the teletext encoded signals corresponding to each of the data rows of said digitally encoded signals resulting in an equality comparison in a teletext line of said television signal as a teletext formated data row on a sequential basis.

Claim 13

In a system of the type including means storing a plurality of digitally encoded signals each representing a selected text/graphics character intended for transmission as a corresponding video signal during the active scanning intervals of a television signal, the method comprising: converting each of said digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character; inserting in a time multiplexed manner said teletext encoded signals as a plurality of teletext formatted data rows in successive teletext lines of said television signal; and amplitude modulating said television signal including said video signal and said teletext lines for transmission on a television channel RF carrier.

Claim 14

In a system of the type including means storing a plurality of digitally encoded signals each representing a selected text/graphics character intended for transmission as a corresponding video signal during the active scanning intervals of a television signal, the method comprising: converting each of said digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character; inserting in a time multiplexed manner said teletext encoded signals as a plurality of teletext formatted data rows in successive teletext lines of said television signal; and amplitude modulating said television signal including said video signal and said teletext lines for transmission on a television channel RF carrier.

Claim 15

In a system of the type including means storing a plurality of digitally encoded signals each representing a selected text/graphics character intended for transmission as a corresponding video signal during the active scanning intervals of a television signal, the method comprising: converting each of said digitally encoded signals to a baseband video signal reflecting the corresponding text/graphics characters and comprising a plurality of horizontal scanning lines of a standard television signal; converting each of said digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character; inserting in a time multiplexed manner said teletext encoded signals as a plurality of teletext formatted data rows in successive teletext lines of said television signal; and amplitude modulating said television signal including said video signal and said teletext lines for transmission on a television channel RF carrier.

Claim 16

In a system of the type including means storing a plurality of digitally encoded signals each representing a selected text/graphics character intended for transmission as a corresponding video signal during the active scanning intervals of a television signal, the method comprising: converting each of said digitally encoded signals to a baseband video signal reflecting the corresponding text/graphics characters and comprising a plurality of horizontal scanning lines of a standard television signal; converting each of said digitally encoded signals to a teletext encoded signal representing a corresponding text/graphics character; inserting in a time multiplexed manner said teletext encoded signals as a plurality of teletext formatted data rows in successive teletext lines of said television signal; and amplitude modulating said television signal including said video signal and said teletext lines for transmission on a television channel RF carrier.

Claim 17

In a system of the type including means storing a plurality of data rows each comprising a plurality of digitally encoded signals each of said digitally encoded signals representing a selected text/graphics character intended for transmission as a corresponding video signal during the active scanning intervals of a television signal, the method comprising: converting the digitally encoded signals comprising each of said data rows to a respective plurality of teletext encoded signals representing the corresponding text/graphics characters; comparing the teletext encoded signals corresponding to each data row of said digitally encoded signals with the corresponding data row during successive active scanning intervals of said television signal; inserting in a time multiplexed manner the teletext encoded signals corresponding to each data row of said digitally encoded signals resulting in an inequality comparison in a teletext line of said television signal as a teletext formatted data row on a priority basis in relation to the teletext encoded signals corresponding to data rows of said digitally encoded signals resulting in an equality comparison; and amplitude modulating said television signal including said video signal and said teletext lines for transmission on a television channel RF carrier.

Claim 18

In a system of the type including means storing a plurality of data rows each comprising a plurality of digitally encoded signals each of said digitally encoded signals representing a selected text/graphics character intended for transmission as a corresponding video signal during the active scanning intervals of a television signal, the method comprising: converting the digitally encoded signals comprising each of said data rows to a respective plurality of teletext encoded signals representing the corresponding text/graphics characters; comparing the teletext encoded signals corresponding to each data row of said digitally encoded signals with the corresponding data row during successive active scanning intervals of said television signal; inserting in a time multiplexed manner the teletext encoded signals corresponding to each data row of said digitally encoded signals resulting in an inequality comparison in a teletext line of said television signal as a teletext formatted data row on a priority basis in relation to the teletext encoded signals corresponding to data rows of said digitally encoded signals resulting in an equality comparison; and amplitude modulating said television signal including said video signal and said teletext lines for transmission on a television channel RF carrier.