VISS signal detecting method for detecting VISS signal of video tape

A computer readable memory storing a computer program performing detection of a VISS signal of a video tape by controlling a computer, said computer program comprising:

• executing a taking-in process of an interval between edges per level edge of said VISS signal;
• performing a detection process of a VISS pulse;
• and
• performing a detection process of said VISS signal on the basis of result of detection in said VISS pulse detection process,
• wherein said edge interval talking-in process is set as an interrupt process having highest priority, and
• wherein said VISS pulse detection process further comprises:
• detecting presence and absence of delay in the process of said VISS pulse detected based on number of occurrence of said edge interval taking-in process occurring up to said VISS pulse detection process by making reference to a count value of an edge for distributing count values of a timer measuring the edge interval of a phase position detection signal added to said VISS signal used in said edge interval taking-in process;
• and
• when delay is caused, performing post process for accurately performing detecting process of said VISS pulse depending upon delay and said edge interval taking-in process in the next cycle.