Method and apparatus for reading data from a disc carrier

An apparatus for supply at an output terminal thereof data read from rotary tracks of a rotating record carrier disc, said apparatus comprising:

• a read head for reading data from said tracks;
• a buffer memory for storing the data read from said tracks by said read head and supplying it at said output terminal during interrupt intervals in which said read head becomes misaligned with said tracks due to one or more temporary mechanical shocks and thereby interrupts the supply of data from said tracks to said memory;
• means for realigning the read head at a later track position from that at which the misalignment occurred;
• means for detecting when the disc has rotated to a position where the read head is radially aligned with but displaced from the position at which misalignment occurred;
• means for causing the read head to move inward one or more tracks until it regains the position at which the misalignment occurred;
• means for causing the read head to read data from said tracks into the buffer memory at a rate greater than that at which data is read out of the buffer memory to said output terminal, until the memory thereby becomes substantially full;
• and
• means for reading data from said tracks into the buffer memory during at least part of a first period between the instant at which the read head becomes realigned with said tracks and the instant at which it reaches the position at which misalignment occurred.

Player apparatus for supplying data from a compact record carrier disc having successive rotary tracks on which the data is recorded;

• comprising:
• a read head for reading data from a track when aligned therewith;
• a buffer memory for storing data read by said read head and supplying it at an output terminal of said apparatus;
• means which, following a misalignment of said read head, realigns it at a position on said disc outward from the position at which the misalignment occurred;
• means for detecting when the disc has rotated so that the read head is radially aligned with the position at which the misalignment occurred;
• means for moving the read head inward one or more tracks until it is restored to the position at which the misalignment occurred;
• means for causing the read head to read data from the disc into said buffer memory at a rate greater than that at which it is read out therefrom to said output terminal, until the buffer memory comes substantially full;
• and
• means for causing the read head to read data from the tracks into the buffer memory during at least part of a first period between the instant at which the read head becomes realigned and the instant at which it again reaches the position at which the misalignment occurred.