Feedback servo for beam power control, tracking control and focus control in an optical disk recording system

A tracking control apparatus for an optical disk recording system comprising:

• beam generating means for emitting a recording beam irradiating on an optical disk;
• detecting means for detecting a tracking error of said recording beam associated with a recording track on said optical disk to generate a corresponding error signal;
• sample pulse generating means for determining the duration of a lower level condition or a higher level condition in an information signal which is to be recorded, said sample pulse generating means for generating a sample pulse corresponding to said duration only if it is determined that said duration is longer than a predetermined time length;
• sample-and-hold means for sample-and-holding said error signal in response to said sample pulse;
• and
• feedback control means for controlling the tracking of said recording beam based on said error signal sample-and-held by said sample-and-hold means.

A focusing control apparatus for an optical disk recording system comprising:

• beam generating means for emitting a recording beam irradiating on an optical disk;
• detecting means for detecting a focus error of said recording beam associated with a recording face on said optical disk to generate a corresponding error signal;
• sample pulse generating means for determining the duration of a lower level condition or a higher level condition in an information signal which is to be recorded, said sample pulse generating means for generating a sample pulse corresponding to said duration only if it is determined that said duration is longer than a predetermined time length;
• sample-and-hold means for sample-and-holding said error signal in response to said sample pulse;
• and
• feedback control means for controlling the focusing of said recording beam based on said error signal sample-and-held by said sample-and-hold means.