Synchronous signal detecting circuit, method, and information storage medium

An apparatus for detecting data in a bit stream, wherein said bit stream contains a sequence of frames, wherein each of said frames comprises a sync pattern and a data portion and has a predetermined number of bits, and wherein said apparatus comprises:

• a detecting circuit which inputs said bit stream, detects a first data pattern in said bit stream that equals said sync pattern, outputs a first detection signal when said first data pattern is detected, detects a second data pattern in said bit stream that equals said sync pattern, and outputs a second detection signal when said second data pattern is detected;
• a counting circuit which is operatively coupled to said detecting circuit and which inputs said bit stream and begins counting bits in said bit stream when said first detection signal is output to generate a count value;
• and
• a synchronization signal generating circuit which is operatively coupled to said counting circuit and which inputs said count value from said counting circuit, compares said count value with a predetermined value, and outputs a synchronization signal when said count value and said predetermined value have a predetermined relationship.

A method for detecting data in a bit stream containing a sequence of frames, wherein each frame has a predetermined number of bits and comprises a sync pattern and a data portion and wherein said method comprises the steps of:

• (a) inputting said bit stream;
• (b) detecting a first data pattern in said bit stream that equals said sync pattern;
• (c) detecting a second data pattern in said bit stream that equals said sync pattern;
• (d) generating a count value by beginning to count bits in said bit stream when said first data pattern is detected;
• and
• (e) comparing said count value with a predetermined value when said second data pattern is detected and outputting a synchronization signal when said count value and said predetermined value have a predetermined relationship.

A method for detecting data in a bit stream containing a sequence of frames, wherein each of said frames comprises a sync pattern and a data portion and has a predetermined number of bits and wherein said method comprises the steps of:

• (a) inputting said bit stream;
• (b) detecting a first data pattern in said bit stream that equals said sync pattern;
• (c) outputting a first detection signal when said first data pattern is detected;
• (d) detecting a second data pattern in said bit stream that equals said sync pattern;
• (e) outputting a second detection signal when said second data pattern is detected;
• (f) generating a count value by beginning to count bits in said bit stream in response to said first detection signal;
• (g) comparing said count value with a predetermined value to determine if said count value and said predetermined value have a predetermined relationship;
• and
• (h) outputting a synchronization signal when said count value and said predetermined value have said predetermined relationship.

An information storage medium in which a software program has been stored, wherein said software program instructs a processor to perform the steps of:

• (a) inputting a bit stream, wherein said bit stream contains a sequence of frames and wherein each frame has a predetermined number of bits and comprises a sync pattern and a data portion;
• (b) detecting a first data pattern in said bit stream that equals said sync pattern;
• (c) detecting a second data pattern in said bit stream that equals said sync pattern;
• (d) generating a count value by beginning to count bits in said bit stream when said first data pattern is detected;
• and
• (e) comparing said count value with a predetermined value when said second data pattern is detected and outputting a synchronization signal when said count value and said predetermined value have a predetermined relationship.