Patent ID: 7965744

Claim:
A transmission system for repeatedly transmitting and receiving at a constant frequency digital audio data of a plurality of channels and auxiliary data required to playback the digital audio data, said transmission system comprising: a transmission apparatus having an encryption unit comprising an encryptor and a plurality of multiplexers in communication with the encryptor so as to encrypt the digital audio data in block data; and a receiving apparatus in communication with the transmission apparatus, the receiving apparatus having a decoding unit comprising a decoder and a plurality of demultiplexers in communication with the decoder so as to decode from the block data the encrypted digital audio data, wherein the block data has a plurality of frames each with time slots reserved for a header portion and a pre-determined encryption unit that comprises an auxiliary data portion and an audio data portion in which the digital audio data is encrypted, wherein the reserved time slots amount to a multiple of n when the predetermined encryption unit is n bytes, wherein the encryptor, the decoder, the multiplexers, and the demultiplexers are responsive to a clock signal and are synchronized with one or more of the others by a periodic signal with a cycle that depends on the number of frames in the block data so that the auxiliary data and the encrypted digital audio data are identified, respectively, with the auxiliary data portion and the audio data portion of respective frames within the block data, and wherein the auxiliary data and the digital audio data of the same channel and at the same bit position among said digital audio data are located at the same position among the respective frames.