System for recording and reading information on a record carrier at a constant scanning speed independent of the bit rate of such information

An apparatus for reading from a track of a record carrier a digital signal which has been recorded thereon, the apparatus comprising:

• scanning means for producing a scanning spot which scans said track with a scanning velocity between 1.2 and 1.4 meters per second;
• read means for using the scanning spot to obtain from said track successive signal portions of a read digital signal which substantially corresponds to the digital signal recorded on said track;
• a buffer memory coupled to said read means for successively receiving therefrom and temporarily storing the signal portions, the signal portions stored in said buffer memory being subsequently read-out therefrom so as to produce an output digital signal;
• and
• control means for (i) interrupting storing of the signal portions in said buffer memory, and causing said scanning means to skip the scanning spot back to a previous track location and resume scanning therefrom, and (ii) resuming storing of the signal portions in said buffer memory when the scanning spot again reaches the track location at which scanning had previously been interrupted, interruption of storing of the signal portions in said buffer memory being such that the degree of filling therein is maintained within predetermined limits.

An apparatus for reading a data compressed digital signal from a track of a record carrier which has been recorded thereon, the apparatus comprising:

• scanning means for producing a scanning spot which scans said track with a predetermined scanning velocity;
• read means for using the scanning spot to obtain successive signal portions of a read digital signal having a read bit rate determined by the predetermined scanning velocity and substantially corresponding to the data compressed digital signal;
• a buffer memory coupled to said read means for successively receiving therefrom and temporarily storing the signal portions, the signal portions stored in said buffer memory being subsequently read-out from said buffer memory so as to produce an output digital signal;
• data decompression means coupled to said buffer memory for providing data decompression of the output digital signal;
• and
• control means for (i) interrupting storing of the signal portions in said buffer memory, and causing said scanning means to skip the scanning spot back to a previous track location and resume scanning therefrom, and (ii) resuming storing of the signal portions in said buffer memory when the scanning spot again reaches the track location at which scanning had previously been interrupted, interruption of storing of the signal portions in said buffer memory being such that the degree of filling therein is maintained within predetermined limits.

A system for recording a record digital signal having successive first signal portions on a track of a record carrier, and subsequently reading said track to obtain a read digital signal having successive second signal portions and substantially corresponding to the record signal recorded on said track, the system comprising:

• scanning means for producing a scanning spot which scans said track;
• write means for using the scanning spot to record the first signal portions on said track;
• read means for using the scanning spot to read said track to obtain the second signal portions;
• an input buffer memory for successively temporarily storing the first signal portions prior to recording them on said track, the first signal portions stored in said input buffer memory being subsequently read-out therefrom to said write means for recording on said track;
• write control means for (i) interrupting read-out of the first signal portions stored in said input buffer memory, and causing said scanning means to skip the scanning spot back to a previous track location and continue scanning therefrom, and (ii) resuming read-out of the first signal portions stored in said input buffer memory when said scanning spot again reaches the track location at which scanning was previously interrupted, interruption of read-out of the first signal portions stored in said input buffer memory being such that the degree of filling of said input buffer is maintained within predetermined limits;
• an output buffer memory for successively temporarily storing the second signal portions obtained by said read means, the second signal portions stored in said output buffer memory being subsequently read-out therefrom;
• and
• read control means for (i) interrupting storing of the second signal portions in said output buffer memory, and causing said scanning means to skip the scanning spot back to a previous track location and continue scanning therefrom, and (ii) resuming storing of the second signal portions in said output buffer memory when the scanning spot again reaches the track location at which scanning was previously interrupted, interruption of storing of the second signal portions in said output buffer memory being such that the degree of filling of said output buffer memory is maintained within predetermined limits;
• whereby a predetermined constant scanning speed may be used to record the first signal portions and read said track to obtain the second signal portions.