Recording disc rotary drive control apparatus

Claim 1

A recording disc rotary drive control apparatus wherein data is written on a recording disc with a substantially constant packing line density, said control apparatus comprising: position detecting means for detecting a distance covered by a pickup for reading said recording disc, the pickup being moved from a reference position in the radial direction thereof, and producing a position detecting signal representing the distance covered thereby; first pulse signal generating means for generating a position pulse signal with a period proportional to said position detecting signal; a motor for rotating said recording disc; second pulse signal generating means for generating a rotational pulse signal having a frequency proportional to the rate of rotation of said motor; switching signal generating means for counting pulses of said position pulse signal starting with the generation of said rotational pulse signal, and producing a switching signal for a period from when a pulse of said rotational pulse signal is produced until the counted value reaches a predetermined value; control signal generating means for generating a control signal for controlling the rate of rotation of said motor according to the output signal of said pickup; means for generating an accelerating signal for increasing the rate of rotation of said motor; driving means for driving said motor according to a driving signal; and switching means for applying said control signal to said motor as said driving signal when said switching signal is present and applying said accelerating signal to said motor as said driving signal while said switching signal is not present.