Data transmission apparatus, data receiving apparatus and method executed thereof

A data receiving apparatus for performing cipher communication, the data receiving apparatus comprising:

• a demodulator section for demodulating a modulated signal generated, in a predetermined modulation method, based on error-correction encoded information data and a combined multi-level signal having accompanying data included therein, and outputting a multi-level signal obtained by the demodulation;
• a multi-level code generation section for generating, by using predetermined key information, a multi-level code sequence in which a signal level changes so as to be approximately random numbers;
• a multi-level identification section for identifying the multi-level signal in accordance with the multi-level code sequence, and outputting data which is identified and reproduced;
• and
• an error-correction decoding section for detecting, from the data reproduced by the multi-level identification section, difference between the combined multi-level signal and the multi-level code sequence, in accordance with predetermined error-correction decoding processing, and outputting a result of the detection as the accompanying data, and also outputting information which is error-correction decoded as the information data.

A data receiving apparatus for performing cipher communication, the data receiving apparatus comprising:

• a demodulator section for demodulating a modulated signal, in a predetermined modulation method, generated based on error-correction encoded information data and a combined multi-level signal having accompanying data included therein, and outputting a multi-level signal obtained by the demodulation;
• a multi-level code generation section for generating, by using predetermined key information and a synchronous signal, a multi-level code sequence in which a signal level changes so as to be approximately random numbers;
• a multi-level identification section for identifying the multi-level signal in accordance with the multi-level code sequence, and outputting data which is identified and reproduced;
• an error-correction decoding section for detecting, from the data reproduced by the multi-level identification section, difference between the combined multi-level signal and the multi-level code sequence, in accordance with predetermined error-correction decoding processing, and outputting a result of the detection as the accompanying data, and also outputting information which is error-correction decoded as the information data;
• and
• a synchronous extraction section for inputting the accompanying data, extracting the synchronous signal synchronizing with the accompanying data in accordance with a predetermined procedure, and outputting the extracted synchronous signal to the multi-level code generation section.

A data transmitting method for performing cipher communication, the data transmitting method comprising:

• a step of generating, by using predetermined key information, a multi-level code sequence in which a signal level changes so as to be approximately random numbers;
• a step of combining accompanying data to the multi-level code sequence with predetermined frequency and generating a combined multi-level signal;
• a step of adding an error-correction code to information data, in accordance with predetermined error-correction encoding processing, and outputting the error-correction encoded information data;
• a step of combining the combined multi-level signal and the error-correction encoded information data, in accordance with predetermined processing, and generating a multi-level signal having a level uniquely corresponding to a combination of levels of both signals represented by the combined multi-level signal and the error-correction encoded information data;
• and
• a step of generating a modulated signal, in a predetermined modulation method, based on the multi-level signal.

A data receiving method for performing cipher communication, the data receiving method comprising:

• a step of demodulating a modulated signal, in a predetermined modulation method, generated based on error-correction encoded information data and a combined multi-level signal having accompanying data included therein, and outputting a multi-level signal obtained by the demodulation;
• a step of generating, by using predetermined key information, a multi-level code sequence in which a signal level changes so as to be approximate random numbers;
• a step of identifying the multi-level signal based on the multi-level code sequence and outputting data which is identified and reproduced;
• and
• a step of detecting, from the data reproduced by the multi-level identification section, difference between the combined multi-level signal and the multi-level code sequence, in accordance with predetermined error-correction decoding processing and outputting a result of the detection as the accompanying data, and also outputting information which is error-correction decoded as the information data.

A data receiving method for performing cipher communication, the data receiving method comprising:

• a step of demodulating a modulated signal, in a predetermined modulation method, generated based on error-correction encoded information data and a combined multi-level signal having accompanying data included therein, and outputting a multi-level signal obtained by the demodulation;
• a step of generating, by using predetermined key information and a synchronous signal, a multi-level code sequence in which a signal level changes so as to be approximate random numbers;
• a step of identifying the multi-level signal in accordance with the multi-level code sequence and outputting data which is identified and reproduced;
• a step of detecting, from the data reproduced by the multi-level identification section, difference between the combined multi-level signal and the multi-level code sequence, in accordance with predetermined error-correction decoding processing, and outputting a result of the detection as the accompanying data, and also outputting information which is error-correction decoded as the information data;
• and
• a step of inputting the accompanying data, extracting the synchronous signal synchronizing with the accompanying data in accordance with a predetermined procedure, and outputting the extracted synchronous signal to the multi-level code generation section.