U.S. Philips Corporation

Gustavus L Van Eijck

Gerardus C Lokhoff

Franciscus A Kneepkens

Petrus H Arts

John F Sherry

Henri J Simons

Systems, apparatus and methods for recording or reproducing from a re-recordable record carrier digital signals, representing a digital audio signal, containing information which results in concealment of a portion of a replica of the digital audio signal during its reproduction to prohibit audio distortions resulting from a boundary between two digital signals, wherein one of those digital signal is newly-recorded over a previously-recorded other digital signal. The concealment information can also be included in auxiliary signals recorded on reproduced from the record carrier along with the digital signals. In a recording apparatus, a digital signal including audio information (i.e., data-reduced samples of sub-band signals derived from sub-band coding a digital audio signal, and bit allocation information and scale factor information relating to the quantized samples) is provided with, via a signal processing unit, mutilated information or a concealment code (possibly included in an auxiliary signal instead) indicating that a portion of the replica of the digital audio signal is to be concealed during its reproduction, and then, recorded on a re-recordable record carrier. The reproducing apparatus acts, via a concealment control signal and a concealment unit, as a result of the mutilated information or the concealment code included in a digital signal (or auxiliary signal) read or received from a re-recordable record carrier, to conceal a portion of the replica of the digital audio signal during its reproduction. In embodiments in which concealment codes are used, a detector is included in the reproducing apparatus to detect the concealment code.

System, apparatus and methods for recording and/or reproducing on and/or

A digital transmission system comprising a transmitter (3, 5, 7, 8) and a receiver (14, 15, 16, 18). The medium (6) comprises an information channel (T.sub.1, T.sub.2, . . . , T.sub.n) and an auxiliary channel (T.sub.n+1). Through the information channel information is transmitted, for example a digital audio signal. Through the auxiliary channel an auxiliary signal is transmitted. This auxiliary signal comprises sync information (100, 101, 102, 103, 104, 105) and additional information (106). The auxiliary signal is composed of successive blocks ( . . . , B.sub.n-1, B.sub.n, B.sub.n+1, . . . ). A first block (B.sub.n) comprises a first block section (header) and a second block section (body). The first block section of the block (B.sub.n) contains a sync word (101) and a first codeword (102), in this order. The first block section of the second directly successive block (B.sub.n+1) contains a sync word (104) and a second codeword (105), in this order. The first codeword (102) expresses that the second block section (106) of the first block (B.sub.n) contains additional information. If there is also additional information in the second block section (107) of the second block, the two codewords are equal. If the block section (107) does not contain additional information, the two codewords are unequal. The first block section of the first block (B.sub.n) further contains a third codeword (100), the sync word (101) and the first codeword ( 102), in this order. The first block section of the scond block (B.sub.n+1) further contains a fourth codeword (103), a sync word (104) and a second coeeword (105), in this order. The fourth codeword also expresses that additional information is contained in the second block section (106) of the first block (B.sub.n). The third codeword is now equal to the fourth codeword if the second block section of the block (B.sub.n-1) directly preceding the first block (B.sub.n) also contains additional information. The two codewords are unequal if the second block section of this block (B.sub.n-1) does not contain additional information. (FIG. 2).

Digital transmission system, transmitter and receiver to be utilized in

Method and apparatus for writing and/or reading an address code on a record carrier, preferably for audio signals, which code consists of a number of preamble pulses, a number of code pulses and a number of post-amble pulses equal to the number of preamble pulses, while between the code pulses check pulses may be inserted.

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Eindhoven, Netherlands

Gustavus L Van Eijck