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

A system for receiving a digital signal at an input thereof and recording it on a track of a record carrier, and subsequently reading the recorded digital signal from said track and deriving therefrom an output digital signal which is supplied at an output of the system;

• the system comprising scanning means for producing a scanning spot which scans said track, write means adapted to use the scanning spot to record the input digital signal on the track, read means adapted to use the scanning spot to read from the track the digital signal which has been recorded thereon, programmable write control means for controlling actuation of said write means, and programmable read control means for controlling actuation of said read means;
• said system being characterized in that it further comprises:
• an input buffer memory coupled between the input of said system and said write means for temporarily storing successive blocks of the data in the received digital signal, the stored data blocks being subsequently read-out to said write means for recording on said track;
• said write control means being programmed to (i) periodically interrupt read-out from the input buffer and concurrently cause the scanning means to skip the scanning spot back to a previous track location and continue scanning from such previous location, and (ii) resume read-out from the input buffer when the scanning spot again reaches the track location at which scanning was previously interrupted;
• the periodic interruptions of read-out from the input buffer being such that the degree of filling of the input buffer is maintained within predetermined limits;
• an output buffer memory coupled between said read means and the output of said system for temporarily storing the successive data blocks read from said track by said read means, the stored data blocks being subsequently read-out from the output buffer to form said output digital signal;
• said read control means being programmed to (i) periodically interrupt read-in to the output buffer and concurrently cause the scanning means to skip the scanning spot back to a previous track location and continue scanning from such previous location, and (ii) resume read-in to the output buffer when the scanning spot again reaches the track location at which scanning was previously interrupted;
• the periodic interruptions of read-in to the output buffer being such that the degree of filling of the output buffer is maintained within predetermined limits;
• whereby the received digital signal is recorded on said track and the recorded digital signal is read from said track at a predetermined constant scanning speed which is independent on the data rates of the received digital signal and the output digital signal.