Methods of broadcasting and receiving high quality sound programs and a receiver device

• US 4,723,285 A
• Filed: 05/29/1985
• Issued: 02/02/1988
• Est. Priority Date: 05/29/1984
• Status: Expired due to Fees

• Current Assignee: Compagnie industrielle des télécommunications CIT-ALCATEL
• Original Assignee: Compagnie industrielle des télécommunications CIT-ALCATEL
• Inventors: Le Roy, Guy, Onno, Guy
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US06/738,717
• Time in Patent Office: 979 Days
• Field of Search: 370/110.1, 381/1, 381/2, 381/3, 358/143, 358/144
• US Class Current: 381/2
• CPC Class Codes: H04H 20/30 by a single channel
• CPC Class Codes: H04H 20/88 Stereophonic broadcast systems multiplex system in general H04J
• CPC Class Codes: H04H 20/89 using three or more audio channels, e.g. triphonic or quadraphonic
• CPC Class Codes: H04H 40/18 Arrangements characterised by circuits or components specially adapted for receiving
• CPC Class Codes: H04J 3/047 Distributors with transistors or integrated circuits

Abstract

A broadcast center delivers each program in digital form and assembles the digital signals of the programs to constitute a digital multiplex which is conveyed to reception points by radio links or by cables. A program is selected by searching for coinicidence between a user-specified number and a channel number in the digital multiplex. The receiver device comprises an input circuit (1), a synchronization word finding cirucit (2), a bit counter (4), a channel counter (5), a comparator (7), a keyboard (8), first (11) and second (10) registers, a parity check register (13), and a digital to analog converter (14).

Claims

1. A device for receiving high-quality sound programs, comprising:

an input circuit having its input connected to a multiplex link conveying said sound programs in digital form in the channels of a frame, and having its output connected to a data link and to a clock link over which the input circuit delivers a recovered clock signal;

a frame synchronizing circuit for searching for a frame synchronization word having its input connected to the input circuit by the data link and having an output connected to respective inputs of a bit counter and a channel counter via an initialization link over which the frame synchronizing circuit delivers an initialization signal (INIT);

the bit counter having an input connected to the clock link and having its output connected to the channel counter;

a first register of the series to parallel type having its input connected to the data link and having a control input connected to the clock link;

a comparator receiving at a first input thereof an output from said channel counter;

an AND gate having one input connected to the parallel output from the first register and having another input connected to the output from the comparator;

a second register of the parallel to parallel type having its input connected to the output from the AND gate and having its output connected to a parity clock register which has its own output connected to a digital to analog converter, the second register having its output connected to a second input of the comparator via a line which conveys two bits for indicating program type, the comparator storing the said program type indication bits.

2. A method of broadcasting audio programs to a plurality of reception points from a broadcast center, said method comprising the following steps:

digitizing each of said audio programs in a pulse code modulation form, said digitizing step including the step of taking a plurality of samples of each of said audio programs, and quantizing and encoding said samples such that the pulse code modulated signals employ several bits for each of said samples, said digitizing step producing a plurality of digital signals corresponding to respective ones of said analog audio programs;

assembling said digital signals of said analog audio programs into a plurality of frames having a high data rate so as to constitute a digital multiplex which operates at the same data rate as a video program transmission digital multiplex, each of said frames comprising a plurality of channels, each of said programs respectively occupying at least one of said channels, wherein each of said channels includes at least one bit indicative of the type of program represented therein; and

delivering the audio programs in digital form to said reception points in accordance with said digitizing and assembling steps.

3. A broadcasting method according to claim 2, wherein said delivering step comprises the step of delivering said digitized audio programs over digital video program transmission and switching equipment.

4. A broadcasting method according to claim 2, wherein said at least one bit indicates whether each of said channels includes a monophonic program, a stereophonic program, or a quadraphonic program, wherein a monophonic program occupies one channel, a stereophonic program occupies an even-numbered channel and an immediately-following odd-numbered channel, and a quadraphonic program occupies an even-numbered channel and three immediately-following channels, said at least one bit including two bits to indicate a quadraphonic program.

5. A method of receiving digitized audio programs, wherein said digitized audio programs are contained in a digital multiplex in a plurality of high data rate frames, such that said digital multiplex operates at the same data rate as a digital video program transmission multiplex, each of said frames containing a plurality of digitized ones of said audio programs, each of said digitized audio programs containing at least one bit indicating whether the program is broadcast in monophonic, stereophonic or quadraphonic form, said method comprising the following steps:

selecting a program number indicative of a program to be received;

comparing said program number with a corresponding channel number in said digital multiplex;

examining said bits indicative of the type of program contained in corresponding channel; and

selecting the appropriate channels in accordance with said examination step, wherein said step of selecting the appropriate channels comprises the following steps;

if a monophonic program is selected, selecting the program selected in accordance with said step of selecting said program number;

if the program selected is a stereophonic program, and the program number is an odd-numbered program, selecting the immediately-preceding even-numbered program;

if the program selected is a stereophonic program, and the program selected in accordance with said step of selecting said program number is an even-numbered program, selecting the program selected in accordance with said step of selecting said program number;

if the program selected is a quadraphonic program, examining two of said bits to determine the correct channel to be selected.