Rotary head type digital signal reproducing apparatus with different modes and tracking control

Claim 1

A rotary head type digital signal reproducing apparatus for playing a magnetic tape pre-recorded with a time division multiplexed signal in one of first and second modes, said time division multiplexed signal comprising a pulse code modulated audio data which is obtained by subjecting an original audio signal to a pulse code modulation and a tracking reference signal, said tracking reference signal which amounts to a predetermined time period being time division multiplexed before and after said pulse code modulated audio data which amounts to a certain time period, said time division multiplexed signal being recorded on successive tracks formed obliquely to a longitudinal direction of the magnetic tape by two rotary heads; on the recording in said second mode, a data quantity per unit time, a frequency of said tracking reference signal, a rotational speed of the rotary heads and a tape transport speed of the magnetic tape being one-half those in said first mode, said rotary head type digital signal reproducing apparatus comprising: reproducing means including two rotary heads for reproducing pre-recorded signals from the magnetic tape; means for setting the tape transport speed to a speed identical to that in said second mode and for setting the rotational speed of the rotary heads to a speed identical to that in said first mode when playing the magnetic tape pre-recorded in said second mode; tracking control means for controlling tracking of the rotary heads based on reproduced tracking reference signals reproduced by said reproducing means, said reproduced tracking reference signals including out of reproduced signals obtained from said reproducing means during a total of four successive scans made by the rotary heads with respect to two mutually adjacent tracks on the magnetic tape at least a reproduced tracking reference signal obtained in an ending portion of a first scan and a reproduced tracking reference signal obtained in a beginning portion of a second scan immediately after said first scan, said first and second scans being successive scans in which a large reproduced output is obtainable by the rotary heads from said two mutually adjacent tracks; and decoding means for decoding the reproduced signals obtained from said reproducing means into the original audio signal based on a reproduced pulse code modulated audio data reproduced from one of said two mutually adjacent tracks during said first scan and a reproduced pulse code modulated audio data reproduced from the other of said two mutually adjacent tracks during said second scan.