| 摘要 |
A circuit is disclosed for serially formatting digital information such as may be provided in a digital audio magnetic tape recorder in a succession of data blocks or frames, each containing the same number of digital bits and in which each frame is delineated by a uniquely occurring digital frame synchronizing signal. The digital information is formatted in a Miller or 3F code in which allowable transitions between successive "1"s and "0"s result in pulses which are 1, 1-1/2 or 2 times the duration of a bit cell, hence giving rise to three characteristic frequencies and the term 3F code. The frame synchronizing signal is generated by providing a signal comprising digital bits 1-0-0-1, which signal in a 3F code is characterized by a transition between the adjacent "0"s, and by appropriately inhibiting that transition, thus creating a pulse which is three times the duration of a unit cell, hence giving rise to a new fourth frequency which cannot be normally created by any succession of "1"s or "0"s. |
