A chicken interferon gene coding for the amino acid sequence of SEQ ID NO:1 is disclosed. The digital GMSK modulation techniques make use of a lookup table and mapping logic to digitally generate GMSK waveforms. Applications of intervertebral implants utilizing arcuate fixation members are particularly suitable when a linear line-of-approach for delivering fixation members is undesirable. The management information area stores a channel table in which a plurality of logical channel numbers are respectively related to a plurality of physical channel numbers for each piece of video data.