Digital signal encoding apparatus and method, digital signal decoding apparatus and method, and digital signal transmission system

A digital signal encoding method for encoding one-bit signals of a plurality of n (n≧2) channels, the one-bit signals being modulated in the delta-sigma manner, comprising the steps of:

• phase-modulating the one-bit signals as original signals to add data of inverted phases thereto;
• adding information data which is related with the one-bit signals to the phase-modulated one-bit signal data having the data of inverted phases added thereto by rearranging the data of inverted phases on the basis of a plurality of m (n≧m≧2) channel unit of the n channels;
• adding independent synchronization patterns which cannot exist in the phase-modulating step or in the information data adding step by arranging a region of a plurality of samples other than a region to which the information data is added in the phase-modulated one-bit signal data every predetermined period, and converting the data of inverted phases in the region in accordance with the phase-modulated one-bit signal data;
• and
• making the numbers of one-bit data [1]s and one-bit data [0]s in the predetermined period, which are generated when the synchronization patterns are added by the synchronization signal adding step, equal to each other by converting the data of inverted phases in a region of the predetermined period so that the difference between the numbers of [1]s and [0]s becomes zero.

A digital signal decoding apparatus for decoding a one-bit data stream transmitted from a digital signal encoding apparatus which phase-modulates one-bit signals as original signals of a plurality of n (n≧2) channels to add data of inverted phases thereto, the one-bit signals being modulated in the delta-sigma manner, and adds information data which is related with the one-bit signals to the phase-modulated one-bit signal data having the data of inverted phases added thereto by rearranging the data of inverted phases on the basis of a plurality of m (n≧m≧2) channel unit of the n channels to generate the one-bit data stream, comprising:

• synchronization signal detecting means for self-extracting synchronization signals by detecting independent synchronization patterns which cannot exist in the phase-modulating processing or in the information data adding processing, and are added by arranging a region of a plurality of samples other than a region to which the information data is added in the one-bit data stream every predetermined period and converting the data of inverted phases in the region in accordance with the phase-modulated one-bit signal data;
• means for detecting the information data by judging the insertion positions of the data of inverted phases in the one-bit data stream based on the synchronization signals detected by the synchronization signal detecting means;
• and
• means for judging original signal data in the one-bit data stream based on the synchronization signals detected by the synchronization signal detecting means, and detecting the original signal data from leading data of each channel every 2n samples.

A digital signal decoding method for decoding a one-bit data stream transmitted from a digital signal encoding apparatus which phase-modulates one-bit signals as original signals of a plurality of n (n≧2) channels to add data of inverted phases thereto, the one-bit signals being modulated in the delta-sigma manner, and adds information data which is related with the one-bit signals to the phase-modulated one-bit signal data having the data of inverted phases added thereto by rearranging the data of inverted phases on the basis of a plurality of m (n≧m≧2) channel unit of the n channels to generate the one-bit data stream, comprising the steps of:

• self-extracting synchronization signals by detecting independent synchronization patterns which cannot exist in the phase-modulating processing or in the information data adding processing, and are added by arranging a region of a plurality of samples other than a region to which the information data is added in the one-bit data stream every predetermined period and converting the data of inverted phases in the region in accordance with the phase-modulated one-bit signal data;
• detecting the information data by judging the insertion positions of the data of inverted phases in the one-bit data stream transmitted from a digital signal encoding apparatus based on the synchronization signals detected by the synchronization signal detecting step;
• and
• judging original signal data in the one-bit data stream transmitted from a digital signal encoding apparatus based on the synchronization signals detected by the synchronization signal detecting step, and detecting the original signal data from leading data of each channel every 2n samples.