TRANSMITTER AND RECEIVER FOR THE TRANSMISSION OF DIGITAL DATA OVER STANDARD TELEVISION CHANNELS

• US 3,743,767 A
• Filed: 10/04/1971
• Issued: 07/03/1973
• Est. Priority Date: 10/04/1971
• Status: Expired due to Term

• Current Assignee: Donald L. Bitzer, Jack Stifle, Michael W. Johnson
• Original Assignee: Donald L. Bitzer, Jack Stifle, Michael W. Johnson
• Inventors: Bitzer, Donald L., Johnson, Michael, Stifle, Jack
• Primary Examiner(s): Murray, Richard
• Application Number:
  US05/186,020
• Time in Patent Office: 638 Days
• Field of Search: 178/5.6,6.8,DIG.13,DIG.23
• US Class Current: 348/463
• CPC Class Codes: H04N 7/025 Systems for the transmission of digital non-picture data, e.g. of text during the active part of a television frame transmission of digital non-picture data during the vertical blanking interval only H04N7/088
• CPC Class Codes: H04N 7/03 Subscription systems therefor

Abstract

Apparatus and a method for the economical distribution of digital data to a number of data terminals using standard commercial television channels including a digital transmitter for transmitting digital data over a video cable and a receiver for receiving the transmitted digital data and selectively distributing the recovered data to the desired data terminals. A method for sending digital data bit by bit over television channels in a field by field manner to a plurality of terminals in a manner such as to greatly simplify the detection of any errors and offering an advantage of decreasing the probability of errors as more data terminals are added to the system.

Claims

1. A system for transmitting and receiving digital data selectively distributable to a plurality of data terminals, utilizing composite line scan horizontal and vertical synchronization (sync) and blanking signals for a teleivision field, compatible with commercial television practice, said system comprising:

means for generating said composite line scan horizontal and vertical sync and blanking signals for a television field;

clock control means for generating a timing signal dividing a line of said television field into discrete time intervals each associated with a respective data terminal;

data storage means for storing said digital data;

data control means receiving said composite sync and blanking signals, said digital data and said timing signal for providing a line scan television field signal compatible with commercial television practice;

said data control means including means for sequentially entering said digital data bit by bit into respective time intervals throughout said line of said television field in response to said timing signal, each bit associated for distribution to a respective data terminal;

a receiver for recovering said digital data from said television field signal for distribution to selected data terminals;

said receiver including means for separating said horizontal and vertical sync information from said television field signal;

means responsive to said horizontal sync information for generating respective line addresses;

phase locked oscillator means including oscillating means providing an oscillating signal at the same rate as said clock control means;

means responsive to said oscillating signal for generating time addresses of each of said discrete time interval in each line of said television field; and

means responsive to a respective line and time address for coupling said data bits sequentially to respective data terminals.

2. A system as claimed in claim 1 wherein said clock control means includes an oscillator providing an outpuT frequency with a corresponding period related to said discrete time intervals in each line of said television field.

3. A system as claimed in claim 1, including means responsive to said vertical sync signal for establishing the beginning of each field, said means further including a line counter activated by said vertical sync signal at the beginning of each field for providing output address signals corresponding to respective lines in each television field.

4. A system as claimed in claim 3, wherein said means responsive to said oscillating signal includes a time counter including means for utilizing said horizontal sync signal to phase lock said oscillating means to said clock control means.

5. A system as claimed in claim 3, wherein said phase locked oscillator means includes a phase comparator, and means for operating said phase comparator only during a predetermined period of each line in said television field.

6. A system as claimed in claim 5, including means for phase locking said phase locked oscillator once for every line in said television field.

7. A method for transmitting and receiving digital data bit by bit in a television field by television field manner and selectively distributable to a plurality of data terminals, utilizing composite line scan horizontal and vertical synchronization (sync) and blanking signals for a television field compatible with commercial television practice, said method comprising:

sequentially entering said digital data bit by bit into respective time intervals throughout a line of said television field, each bit associated for distribution to a respective data terminal;

providing a line scan television field signal compatible with commercial television practice, said signal including said composite sync and blanking signals and said sequentially entered digital data;

receiving said digital data from said line of said television field for distribution to selected data terminals;

sequentially addressing respective data terminals in response to said horizontal and vertical sync information from said line scan television field signal; and

sequentially coupling said data bits to said respectively addressed data terminals.

8. A method for transmitting and receiving digital data selectively distributable to a plurality of data terminals, utilizing composite line scan horizontal and vertical synchronization (sync) and blanking signals for a television field, compatible with commercial television practice, said method comprising:

generating said composite line scan horizontal and vertical sync and blanking signals for a television field;

generating a timing signal dividing a line of said television field into discrete time intervals each associated with a respective data terminal;

storing said digital data;

receiving said composite sync and blanking signals, said digital data and said timing signal for providing a line scan television field signal compatible with commercial television practice;

sequentially entering said digital data bit by bit into respective time intervals throughout said line of said television field in respone to said timing signal, each bit associated for distribution to a respective data terminal;

recovering said digital data from said television field signal for distribution to selected data terminals;

separating said horizontal and vertical sync information from said television field signal;

generating respective line addresses in response to said horizontal sync information;

providing an oscillating signal at the same rate as said clock control means;

generating time addresses of each of said discrete time intervals in each line of said television field in response to said oscillating signal; and

coupling said data bits sequentially to respective data terminals in response to a respective line and time address.