METHOD AND APPARATUS FOR DECODING DIGITAL SYNCHRONIZING SIGNAL

摘要

PURPOSE:To decode a synchronizing signal separated at a variable interval by measuring a bit period interval between starts of two consecutive synchronizing signals and using a window whose position changes depending on the change of the distance with respect to the interval so as to retrieve a synchronizing signal pattern. CONSTITUTION:In case the interval of the start between consecutive synchronizing signals in an input signal is varied in the range of P+ or -Q bit period, the bit period interval of the said starts is measured by the 1st detection of the pattern and the window comprising the said interval and whose position is changed in response to the interval change is used to detect the pattern in the input signal. Then a synchronizing pulse synchronous with the consecutive synchronizing signal detected by the window is supplied. The window corresponding to the P+ or -Q bit period is used for the 1st detection. A window prolonged for 1 bit period for both sides of the interval is used for the succeeding detection. Even if the synchronizing signal does not appear at a constant interval, the synchronizing signals are decoded in this way.