光碟機變速讀取模式與主軸馬達轉速控制之分析

Abstract

本論文主要在分析數種CD-ROM光碟機的變速讀取模式，使得光碟機在原系 統架構下，藉著主軸馬達控制方式的改變，能得到較高的平均資料傳輸率 ，並降低平均讀取時間。首先，我們研究主軸馬達伺服系統各訊號之間的 關係，以了解變速讀取系統之可行性。其次，比較CD-ROM光碟機在CLV、 CAV、ZCAV與CAV-CLV各種讀取模式的平均資料傳輸率與平均讀取時間之性 能，以了解如何在馬達轉速與解碼電路的雙重限制之下，規畫最佳的速度 曲線。接著，我們討論了在實際CD-ROM光碟機系統中，變速讀取模式的可 能實現方式。最後，藉由硬品迴路的模擬與實驗，我們成功的控制了主軸 馬達在變速讀取模式下的轉速變化，間接地印證了光碟機變速讀取模式的 可行性。 This paper describes several variable bit rate readout algorithms which canbe used to control the speed of the spindle motor of a CD-ROM drive. While maintaining the servo-mechanical requirement, these algorithms have the capability to increase the average bit rate and decrease the average access time. Firstly,by analyzing the relationship between the signals in the spindle servo system of a CD-ROM drive, the accessibility of variable bit rate readout modes of a CD-ROM system are recognized. Secondly, by comparing the performance of theaverage bit rate and average access time between CLV, CAV, ZCLV, CAV-CLV readoutmodes, the optimal speed profile designs under the limitation of motor speedand decoding circuit are obtained. Thirdly, a realization method of variablebit rate readout systems for practical CD-ROM drivers is proposed. Finally,by using the concept of hardware in the loop, the speed of the spindle motoris controlled to follow the speed profile for different variable bit rate readout modes. These results verify the proposed variable bit rate readout CD-ROMsystems.