Disc players

A disc player for reproducing an information signal digitally modulated in the form of a run length limited code, having predetermined maximum and minimum run time lengths, recorded with constant recording density in a spiral track on a disc, said disc player comprising:

• driving means for rotating said disc;
• pickup means for scanning said spiral track on said rotating disc and reproducing the signal recorded therein;
• first detecting means receiving the reproduced signal from said pickup means for detecting a first time interval of constant signal level representing one of said maximum and minimum run time lengths and providing a drive control signal having a level varying in response to the detected length of said first interval;
• means connected to said driving means and receiving said drive control signal for changing an operating mode of said drive means, whereby said driving means is operated to maintain a predetermined constant length of said first time interval corresponding to a selected scanning speed of said pickup means relative to said disc;
• second detecting means receiving said reproduced signal from said pickup means for detecting when a second time interval of constant signal level in said reproduced signal exceeds a predetermined maximum time interval representing said maximum run time length at said selected scanning speed and providing an overspeed control signal in response thereto;
• and
• controller means response to said overspeed control signal for producing a mode signal fed to said means for changing an operating mode of said drive means, whereby the operating mode of said driving means is changed.