Method for simultaneous teletext and analog signal transmission

• US 4,413,281 A
• Filed: 06/26/1981
• Issued: 11/01/1983
• Est. Priority Date: 07/01/1980
• Status: Expired due to Term

• Current Assignee: Alcatel Bell SDT SA (Thales SA)
• Original Assignee: ACEC Ateliers de Constructions Electriques de Charleroi
• Inventors: Thonnart, Paul
• Primary Examiner(s): Martin, John C.
• Application Number:
  US06/277,672
• Time in Patent Office: 858 Days
• Field of Search: 358/147, 358/142, 358/143, 358/146, 358/114, 358/86
• US Class Current: 348/461
• CPC Class Codes: H04N 1/00098 via a television channel, e.g. for a series of still pictures with or without sound
• 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 7/17318 Direct or substantially direct transmission and handling of requests

Abstract

Disclosed is a process for the transmission of information over television networks wherein certain information is encoded in digital form and transmitted by supplementing and/or replacing the information forming the conventional program. The digital information is received by a conventional receiving set equipped with a decoding, memory and detector means. Information is transmitted in the form of analog signals subdivided into scans or groups of scans, each scan having associated identifying material. The information transmitted in digital form has other identifying material and is transmitted generally synchronously with the corresponding information in analog form. The transmissions are received by receivers with detectors sensitive to the identifying material and which have analog-digital and inverse conversion means as well as memory and decoding means to reproduce the information contained in the analog and digital signals.

Claims

1. A process for the transmission of information over television networks comprising:

(a) generating analog signals representing groups of scans of an image, each of said scans having a duration approximately equal to the time necessary to transmit one scan of a television image;

(b) generating first identifying messages and combining them with the analog signals representing said scans;

(c) generating teletext signals in digital form, said teletext signals being associated with said groups of scans;

(d) generating second identifying messages and combining them with said teletext signals;

(e) selecting analog signals identified by said first identifying messages and associated teletext signals identified by said second identifying messages and transmitting both approximately at the same time;

(f) receiving said analog and teletext signals with a receiver responsive to said first and second identifying messages;

(g) decoding said analog and associated teletext signals; and

(h) reproducing said decoded analog and associated teletext signals for one of simultaneous or successive reproduction.

2. The process of claim 1, wherein said teletext signals are transmitted over different channels from the analog signals.

3. The process of claim 1, wherein the teletext and analog signals are transmitted over the same transmission channel, the teletext signals being transmitted during predetermined periods of time on said scans of the analog signals.

4. The process of claim 3, wherein the predetermined periods of time are periods where no analog signals are being transmitted.

5. The process of claim 1 or 2 or 3, wherein at least some of said analog signals are video signals.

6. The process of claim 1 or 2 or 3, wherein at least some of said analog signals are audio signals.

7. The process of claim 1 or 2 or 3 or 4, wherein the step of receiving further includes separating said analog and teletext signals, detecting by means of a message detector and logic information contained in said analog and teletext signals and recording said information in a memory.