Apparatus for decoding digital information processed for inclusion in wide band T.V. video signal

• US 4,394,687 A
• Filed: 12/30/1980
• Issued: 07/19/1983
• Est. Priority Date: 04/30/1979
• Status: Expired due to Term

• Current Assignee: Independent Broadcasting Authority A British Body Corporate
• Original Assignee: John J. Moyce, Peter R. Hutt
• Inventors: Hutt, Peter R., Moyce, John J.
• Primary Examiner(s): RICHARDSON, ROBERT
• Application Number:
  US06/227,050
• Time in Patent Office: 931 Days
• Field of Search: 358/141, 358/142, 358/146, 358/147, 358/188
• US Class Current: 348/467
• CPC Class Codes: H04N 7/0882 for the transmission of character code signals, e.g. for teletext circuits for the digital non-picture data signal H04N7/035

Abstract

Digital information signals representing information to be displayed on a television receiver are received separate from the wide band video signals and stored for display in a predetermined number of rows and columns. The digital information signals are displayed in predetermined number of rows and columns of characters with the information signals being transmitted in lines, each of which contain data relating to a number of characters less than the predetermined number of columns in the display. The control code is also transmitted in the digital information signals and extracted to control the storage addressing of the digital information signals in a storage device by appropriate row and column addresses.

Claims

1. A television receiver system for receiving digital information signals transmitted with a conventional wide band video signal to enable display of the information represented by the digital information signal in a display having predetermined numbers of rows and columns of characters, the information signals being transmitted in lines each of which contain data relating to a number of characters less than the predetermined number of columns in the display, comprising:

means for receiving the digital information signals separated from the wide band video signals;

means for storing said digital information signals for display in said predetermined numbers of rows and columns;

means for detecting in the digital information signals a tabulation control code indicative of the presence of digital information relating to two rows of the display in an information line and including row and column addressing codes and wherein said means for detecting includes row address and column address detecting means for respectively detecting the row and column addressing codes, means for retaining an immediately previous row address for a subsequently received data information line when said detecting means detects said control code, and wherein the column address detecting means controls the retaining means to change the row address to that received from said subsequently received data information line at a time determined by the detected column address received from said subsequently received data information line; and

means for controlling the storage addressing of said digital information signals in said means for storing in accordance with said control code to ensure proper read out for display of the information.

2. A televison receiver system according to claim 1, and further comprising additional detecting means for detecting errors in the information signal lines to inhibit writing of incorrect information into said means for storing said digital information signals.

3. A television receiver system according to claim 1, wherein said detecting means further includes a logic circuit for detecting the presence of a single binary digit at a preselected location in said control code.

4. A television receiver system according to claim 1, wherein the control code is comprised within the column address and said detecting means further includes a logic circuit connected to said column address detecting means for deriving said control code from the column address.

5. A television receiver system according to claim 4, wherein said logic circuit includes means for detecting the column address indicative of the start of a row to indicate the presence of information relating to only one row.

6. A television system according to claim 1, wherein the column address contains information concerning the correct sequence of lines of the information signals and further comprising a logic circuit connected to said column address detecting means for deriving a control signal from said column address code for the detection of errors.

7. A television receiver system according to claim 6, wherein said logic circuit includes means for monitoring the least significant digit of the column address code.