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公开(公告)号：US4675761A
公开(公告)日：1987-06-23
申请号：US835617
申请日：1986-03-03
CPC分类号： G11B5/5526
摘要： An apparatus and method are disclosed for positioning magnetic heads relative to the recording tracks of a recording medium such as a floppy disk having circular, concentric recording tracks formed thereon. The magnetic heads are mounted on a head carriage, and the head carriage is moved, in response to received command pulses, so that the heads are moved linearly, by step increments, along a radius of the floppy disk. The heads are thereby moved across the spaced tracks on the disk, with each incremental movement of the heads being a distance less than the distance between the tracks, and being, for example, one-half or one-fourth of the total distance between tracks. Acoustic noise due to head movement is minimized by moving the heads by increments less than the distance between the tracks, with such movement avoiding exciting the resonances of the head moving apparatus. The magnetic heads are initially moved at a rate known to avoid exciting the resonance and, during such initial movement, the rate of received command pulses is determined. If the received command pulse rate is within a predetermined range, and is a rate that will not excite resonance, continued movement of the head is at the rate of the received command pulses.
摘要翻译： 公开了一种用于将磁头相对于记录介质的记录轨道定位的装置和方法，诸如形成有圆形同心记录磁道的软盘。 磁头安装在头部托架上，并且头托架响应于接收到的命令脉冲而移动，使得头部沿着软盘的半径以逐步的增量线性移动。 磁头由此移动到磁盘上的间隔的磁道上，磁头的每次增量运动的距离都小于轨道之间的距离，并且例如是轨道之间的总距离的一半或四分之一 。 通过以小于轨道之间的距离的方式移动头部，使头部运动引起的声音噪声最小化，避免激发头部移动装置的共振。 磁头首先以已知的速度移动以避免激发谐振，并且在这样的初始移动期间确定接收到的命令脉冲的速率。 如果接收到的指令脉冲速率在预定范围内，并且是不会激发共振的速率，则头的继续移动处于接收到的命令脉冲的速率。
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公开(公告)号：US4564794A
公开(公告)日：1986-01-14
申请号：US737003
申请日：1985-05-23
CPC分类号： H02P23/186 , Y10S388/902 , Y10S388/911 , Y10S388/912
摘要： The speed of a DC motor (10) is controlled by a servo which includes a digital phase lock loop. The motor drives a tachometer whose pulse (22) frequency is low relative to the frequency of a clock (21). The clock continuously drives a counter (200) whose ever increasing number content is gated to a data latch (26) upon the occurrence of each successive tachometer pulse, thus this data latch contains a first time-number of ever increasing magnitude. A second data latch (24) contains a second number. The difference in magnitude of two consecutive time-numbers is indicative of motor speed. Initially, this second number is set to contain a reference number (REF) which is equal in magnitude to the number of clock pulses which will occur between adjacent tachometer pulses when the motor is running at desired speed. A pair of limit numbers (RANGEL and RANGEH) are provided to define the upper and lower limits of servo saturation. The difference between the first number and the second number is detected upon the occurrence of each tachometer pulse to generate a third or difference number (ERRA). This difference number is compared to the two limit numbers to determine if the servo is in saturation. If it is not in saturation, the second number is reset to a value which is equal to the old value plus the reference number. If the servo is in saturation, the second number is reset to a number which is a function of the first number, the reference number, and that limit number which is associated with the particular mode of saturation.
摘要翻译： DC马达（10）的速度由包括数字锁相环的伺服控制。 电机驱动相对于时钟（21）频率的脉冲（22）频率较低的转速计。 在每次连续转速计脉冲发生时，时钟连续地驱动其越来越多的数量内容被门控到数据锁存器（26）的计数器（200），因此该数据锁存器包含不断增加的幅度的第一时间数量。 第二数据锁存器（24）包含第二数字。 两个连续时间数字的大小差异表示电机速度。 最初，该第二数字被设置为包含参考数字（REF），该参考数字在幅度上等于当电动机以所需速度运行时将在相邻转速计脉冲之间发生的时钟脉冲数。 提供一对极限数（RANGEL和RANGEH）来定义伺服饱和度的上限和下限。 在发生每个转速计脉冲以产生第三或差数（ERRA）时，检测第一数和第二数之间的差。 将该差数与两个限制数进行比较，以确定伺服是否处于饱和状态。 如果不是饱和，则第二个数字被重置为等于旧值加参考号的值。 如果伺服器处于饱和状态，则第二个数字被复位为与特定饱和模式相关联的第一个数字，参考号和限制数的函数的数字。
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