Tracking control circuit for maintaining substantial balance between reproduced signal levels from plural rotary magnetic heads when tracking control is applied in respect to only one of the heads

摘要

A magnetic recording and reproducing apparatus includes a rotary drum that has a magnetic tape wound around the drum and first and second magnetic heads mounted on the drum for scanning the magnetic tape as the tape is advanced to reproduce an information signal recorded in successive oblique tracks on the tape. The first magnetic head has a magnetic gap that is inclined in a clockwise direction, relative to a line that is normal to a scanning direction of the magnetic heads, when viewed from the rotary drum. The second magnetic head has a magnetic gap that is inclined in a counterclockwise direction, relative to a line that is normal to the scanning direction of the magnetic heads, when viewed from the rotary drum. A tracking control circuit controls the scanning locus of the first magnetic head relative to an oblique track which the first magnetic head reproduces. The first head is selected for control because it inherently has a weaker signal due to the greater inclination of its azimuth angle from the direction of orientation of the magnetic material on the tape. Also, a tracking control pilot signal is generated by adding respective control bits to subdivisions of predetermined length of a digital recording signal. In this way, a low frequency component is superimposed on the digital signal to form the tracking control pilot signal.