Method and apparatus for providing high speed recording on an optical medium

Abstract

A system and method for controlling the position of an optical head of a disc during high speed recording. In one embodiment of the method, an optical disc has a plurality of tracks. The method comprises implementing CLV recording by said optical drive, determining a wobble signal based on address information contained in said plurality of tracks of said optical disk and determining a wobble clock signal based on said wobble signal. The method further comprises decoding said wobble clock signal by a decoder, said decoder to provide a sync clock signal to an encoder loop circuit, said sync clock signal based on said wobble clock signal generating an encoder clock signal using said encoder loop circuit. In addition, the method comprises comparing said sync clock signal to said encoder clock signal to provide a position command to position the optical head of said optical drive.

What is claimed:  
     
         1 . A method for positioning an optical head of an optical disc, said optical disc having a plurality of tracks, the method comprising: 
 operating in a constant linear velocity (CLV) recording mode;    determining a wobble signal based on address information contained in said plurality of tracks of said optical disc;    determining a wobble clock signal based on said wobble signal;    decoding said wobble clock signal by a decoder, to provide a sync clock signal to an encoder loop circuit, said sync clock signal based on said wobble clock signal;    generating an encoder clock signal by said encoder loop circuit; and,    comparing said sync clock signal to said encoder clock signal to provide a output signal to position the optical head of said optical drive.    
     
     
         2 . The method of  claim 1  wherein said wobble signal is a frequency modulated Frequency Shift Key (FSK) signal with bi-phase coded address information.  
     
     
         3 . The method of  claim 2  wherein determining a wobble clock signal based on said wobble signal comprises determining, by a CLV servo circuit, a wobble clock signal based on said wobble signal, said CLV servo circuit to drive a spindle motor of said optical drive to maintain said constant linear velocity.  
     
     
         4 . The method of  claim 1  wherein generating an encoder clock signal comprises receiving the sync clock signal from said decoder by said encoder loop circuit, multiplying said sync clock signal by a predetermined number to generate the encoder clock signal.  
     
     
         5 . The method of  claim 1  wherein said decoder is an Absolute Time in Pre-Groove (ATIP) decoder and said sync clock signal is an ATIP sync clock signal.  
     
     
         6 . The method of  claim 1  wherein said encoder loop circuit is a type II Encoder Phase Lock Loop circuit.  
     
     
         7 . The method of  claim 1  further comprising receiving, during a seek mode, a reference clock signal by said encoder loop circuit, said encoder loop circuit to lock onto said reference clock signal during said seek mode instead of said sync clock signal.  
     
     
         8 . The method of  claim 1  wherein entering the CLV recording mode comprises entering the CLV recording mode, phase locking the sync clock signal with a reference clock signal upon entering said CLV recording mode.  
     
     
         9 . The method of  claim 8 , wherein said sync clock signal is compared with said reference clock signal only upon an occurrence of an irregularity.  
     
     
         10 . The method of  claim 1  further comprising: 
 entering a continuous angular velocity (CAV) recording mode;  
 varying the sync clock signal as the optical head of the optical drive moves from an inner diameter to an outer diameter of said optical disk; and,  
 tracking said sync clock signal with the encoder loop circuit.  
 
     
     
         11 . The method of  claim 10  wherein a write power of the optical head depends on a write speed of said optical drive, said write power to vary linearly between a first point at the inner diameter and a destination point.  
     
     
         12 . The method of  claim 1  further comprising: 
 providing a partial CAV recording mode, said partial recording mode comprising: 
 performing a CAV recording operation under a recording rate limit is reached,  
 switching a motor drive of the optical drive from a CAV servo to a CLV servo; and,  
 maintaining said encoder clock signal during said switching.  
 
 
     
     
         13 . A system for positioning an optical head during a recording operation comprising: 
 an optical disc containing data, said optical head to perform the recording operation on said optical disc and to produce a wobble signal based on address information contained on said optical disc;    a controller circuit to cause said system to operate in a constant linear velocity (CLV) recording mode;    a tracking CLV circuit to receive the wobble signal from the optical head and to determine a wobble clock signal based on said wobble signal;    a decoder, coupled to the tracking CLV circuit, to receive said wobble clock signal and to generate a sync clock signal, said sync clock signal based on said wobble clock signal;    an encoder loop circuit, coupled to the decoder, to receive said sync clock signal and to generate an encoder clock signal; and,    an encoder block, coupled to the encoder loop circuit and the decoder, said encoder block to receive and compare said sync clock signal to said encoder clock signal and, based on said comparing, provide a position command to position the optical head during said recording operation.    
     
     
         14 . The system of  claim 13  wherein said wobble signal is a frequency modulated Frequency Shift Key (FSK) signal with bi-phase coded address information.  
     
     
         15 . The system of  claim 14  wherein determining a wobble clock signal based on said wobble signal comprises determining a wobble clock signal based on said wobble signal using a CLV servo circuit, said CLV servo circuit to drive a spindle motor of said optical drive to maintain said constant linear velocity.  
     
     
         16 . The method of  claim 13  wherein generating an encoder clock signal comprises receiving the sync clock signal from said decoder by said encoder loop circuit, multiplying said sync clock signal by a predetermined number to generate the encoder clock signal.  
     
     
         17 . The method of  claim 13  wherein said decoder is an Absolute Time in Pre-Groove (ATIP) decoder and said sync clock signal is an ATIP sync clock signal.  
     
     
         18 . The method of  claim 13  wherein said encoder loop circuit is a type II Encoder Phase Lock Loop circuit.  
     
     
         19 . The method of  claim 13  further comprising receiving, during a seek mode, a reference clock signal by said encoder loop circuit, said encoder loop circuit to lock onto said reference clock signal during said seek mode instead of said sync clock signal.  
     
     
         20 . The method of  claim 13  wherein entering the CLV recording mode comprises entering the CLV recording mode, phase locking the sync clock signal with a reference clock signal upon entering said CLV recording mode.  
     
     
         21 . The method of  claim 13 , wherein said sync clock signal is compared with said reference clock signal only upon an occurrence of an irregularity.  
     
     
         22 . The method of  claim 13  further comprising: 
 entering a continuous angular velocity (CAV) recording mode;  
 varying the sync clock signal as the optical head of the optical drive moves from an inner diameter to an outer diameter of said optical disk; and,  
 tracking said sync clock signal with the encoder loop circuit.  
 
     
     
         23 . The method of  claim 22  wherein a write power of the optical head depends on a write speed of said optical drive, said write power to vary linearly between a first point at the inner diameter and a destination point.  
     
     
         24 . The method of  claim 13  further comprising: 
 entering a partial CAV recording mode, said partial recording mode comprised of: 
 performing a CAV recording operation under a recording rate limit is reached,  
 switching a motor drive of the optical drive from a CAV servo to a CLV servo; and,  
 maintaining said encoder clock signal during said switching.  
 
 
     
     
         25 . A method for positioning an optical head of an optical disk during a recording operation, said optical disk having a plurality of tracks, the method comprising: 
 implementing a continuous angular velocity (CAV) recording mode;    varying a sync clock signal as the optical head of the optical drive moves from an inner diameter to an outer diameter of said optical disk; and,    tracking said sync clock signal with an encoder loop circuit.    
     
     
         26 . The method of  claim 25  further comprising: 
 varying a write power of said optical head based on a write speed of said optical drive, said write power to vary linearly between a start point and a destination point during the recording operation.  
 
     
     
         27 . The method of  claim 25  further comprising: 
 entering a partial CAV recording mode when a predetermined recording data rate limit is reach;  
 coupling a continuous linear velocity (CLV) circuit to the optical head; and,  
 maintaining an encoder clock signal used during the CAV recording mode after entering the partial CAV recording mode.