Tracking jump compensator for optical disc reproducing apparatus

An optical disk reproducing apparatus in which an optical disk is rotated at a first rotational speed on the basis of a first master clock signal and a light spot is irradiated on said optical disk for reproducing digital data comprising:

• memory means into and from which digital data reproduced from said optical disc are sequentially written and read out, respectively,
• track jump detection means detecting a track jump of said light spot during reproduction from a desired position to an undesired position on said optical disk caused by an external mechanical shock and for generating a track jump detection signal,
• resetting means for resetting said light spot to a position just ahead of said track jump upon receiving said track jump detection signal from said track jump detection means,
• second master clock generating means for generating a second master clock signal of a higher frequency than said first master clock signal, and
• control means for continuously reading out digital data stored in said memory means on the basis of said first master clock signal on detection of a track jump by said track jump detection means, said control means causing rotation of said optical disk at a second rotational speed higher than said first rotational speed on the basis of said second master clock signal for a predetermined period after resetting of said light spot by said resetting means and writing the reproduced digital data in said memory means on the basis of said second master clock signal,
• wherein said memory means includes a RAM for storing said digital data in a predetermined address, a write generating means selectively supplied with said first or second master clock signals for generating write addresses for writing in said RAM, read address generating means supplied with said first master clock signal for generating readout addresses for reading from said RAM, said readout addresses being the same addresses as the write addresses generated by said write generating means with a delay of a predetermined period longer than a time period necessary for resetting said light spot by said resetting means, and address comparison means for comparing write addresses generated by said write address generating means with readout addresses generated by said readout address generating means and responsive to a compared difference therebetween to generate a control signal for selecting said first or second master clock signals supplied to said write address generating means.