Abstract: A time synchronization system includes: a master including: a main processor to which a first IP address is assigned; and a time synchronization processor to which a second IP address is assigned; a plurality of slaves configured to send a first packet whose destination is the first IP address and a second packet whose destination is the second IP address to the master; and a relay configured to send the first packet to the main processor and to send the second packet to the time synchronization processor. The main processor receives the first packet from the relay and performs a certain process on the first packet. The time synchronization processor receives the second packet from the relay and performs a time synchronization process between the master and said one of the slaves based on the second packet.

Abstract: Servo error signal circuitry apparatus and methods are described. The difference between two bottom envelope signals SEbtm and SFbtm is calculated by a subtracter (40) to generate a difference signal (SEbtm?SFbtm). The difference signal (SEbtm?SFbtm) is input as an alignment signal (AL) to an equalizer (42) and as a basic tracking error signal to the positive input terminal of a second subtracter (52). On the other hand, the difference between two top envelope signals SEtop and SFtop is calculated by a third subtracter (48) to generate a difference signal (SEtop?SFtop). The signal K(SEtop?SFtop) obtained by multiplying a coefficient K with the difference signal using a coefficient multiplier (50) is input to the negative input terminal of the second subtracter (52). The difference signal {(SEbtm?SFbtm)?K(SEtop?SFtop)} output from the second subtracter (52) is used as an offset corrected tracking error signal.

Abstract: A servo error detector usable in an optical disk system is provided. An envelope detecting unit (24) detects the top envelopes and bottom envelopes of RF signals SA–SH, and top envelope signals SAtop–SHtop and bottom envelope signals SAbtm–SHbtm that represent the top envelope waveforms and bottom envelope waveforms of RF signals output from an optical detector. An analog/digital conversion unit (26) converts analog top envelope signals SAtop–SHtop and bottom envelope signals SAbtm–SHbtm corresponding to all input RF signals SA–SH to digital top envelope signals QAtop–QHtop and bottom envelope signals QAbtm–QHbtm, respectively. A digital operation unit (28) performs digital operation treatment for digital top envelope signals QAtop–QHtop and bottom envelope signals QAbtm–QHbtm to generate various servo error signals.

Abstract: A servo error detector usable in an optical disk system is provided. An envelope detecting unit (24) detects the top envelopes and bottom envelopes of RF signals SA−SH, and top envelope signals SAtop−SHtop and bottom envelope signals SAbtm−SHbtm that represent the top envelope waveforms and bottom envelope waveforms of RF signals output from an optical detector. An analog/digital conversion unit (26) converts analog top envelope signals SAtop−SHtop and bottom envelope signals SAbtm−SHbtm corresponding to all input RF signals SA−SH to digital top envelope signals QAtop−QHtop and bottom envelope signals QAbtm−QHbtm, respectively. A digital operation unit (28) performs digital operation treatment for digital top envelope signals QAtop−QHtop and bottom envelope signals QAbtm−QHbtm to generate various servo error signals.

Abstract: Servo error signal circuitry apparatus and methods are described. The difference between two bottom envelope signals SEbtm and SFbtm is calculated by a subtracter (40) to generate a difference signal (SEbtm−SFbtm). The difference signal (SEbtm−SFbtm) is input as an alignment signal (AL) to an equalizer (42) and as a basic tracking error signal to the positive input terminal of a second subtracter (52). On the other hand, the difference between two top envelope signals SEtop and SFtop is calculated by a third subtracter (48) to generate a difference signal (SEtop−SFtop). The signal K(SEtop−SFtop) obtained by multiplying a coefficient K with the difference signal using a coefficient multiplier (50) is input to the negative input terminal of the second subtracter (52). The difference signal {(SEbtm−SFbtm)−K(SEtop−SFtop)} output from the second subtracter (52) is used as an offset corrected tracking error signal.