| 摘要 |
PURPOSE:To improve resistance to a code error and to apply a system even to variable length frame constitution by combining plural characteristic words with characteristic words or noncharacteristic words which are as many as said characteristic words alternately without overlapping, and thus constituting plural control codes. CONSTITUTION:In a figure, P1-P6 are characteristic words, which are never generated in a data sequence of codes other than control codes. Further, P7-P12 are characteristic words or noncharacteristic words which are low in generation frequency in a data sequence. Respective elements are extracted from a group of P1-P6 and a group of P7-P12 alternately without overlapping to constitute the control codes C1, C2, and C3. On a transmission side, a control code is inserted into each frame, which is sent to a reception side. When the data sequence is received on the reception side, on the other hand, it is decided whether or not a combination of >=2 words containing >=1 characteristic code in four successive words coincides with a combination present in the control code and when so, it is considered that there is the corresponding control code at a corresponding position. |
