公开(公告)号：WO1997017696A1

公开(公告)日：1997-05-15

申请号：PCT/US1996018094

申请日：1996-11-08

Applicant: PHASE METRICS

Inventor： PHASE METRICS ,  INBAR, Michael

IPC: G11B05/02

CPC classification number: H03D1/2281 ,  G01R33/1207 ,  G11B5/012 ,  G11B20/1816 ,  G11B27/36 ,  G11B33/10

Abstract: An apparatus and method for demodulating an amplitude modulated read signal generated by a magnetic head (12) of a hard disk drive. The apparatus includes a pair of serially connected track and hold circuits (16, 20) that receive the read signal. The track or hold state of each circuit is controlled by a phase lock loop circuit (24) which also receives the read signal. The first track and hold circuit initially tracks the read signal to a peak value. The second track and hold circuit tracks the output of the first circuit. The output signals are compared to a threshold value to detect bit errors in the signal. The constant output signals provide additional energy to the detection circuit to minimize the number of false error signals from the comparator circuit (32).

Abstract translation: 一种用于解调由硬盘驱动器的磁头（12）产生的调幅读信号的装置和方法。 该装置包括一对串行连接的跟踪和保持电路（16,20），其接收读取信号。 每个电路的跟踪或保持状态由也接收读取信号的锁相环电路（24）控制。 第一个跟踪和保持电路首先将读取的信号跟踪到一个峰值。 第二轨道和保持电路跟踪第一电路的输出。 将输出信号与阈值进行比较，以检测信号中的位错误。 恒定输出信号为检测电路提供额外的能量以最小化来自比较器电路（32）的误差信号的数量。

公开(公告)号：WO1996010192A1

公开(公告)日：1996-04-04

申请号：PCT/US1995011699

申请日：1995-09-15

Applicant: PHASE METRICS

Inventor： PHASE METRICS ,  INBAR, Michael

IPC: G01R33/12

CPC classification number: G01R33/1253 ,  G11B5/455 ,  G11B2005/0016

Abstract: A tester for measuring the resistance of magnetoresistive heads as a function of the magnetic field applied to the heads is disclosed. The tester applies a time varying magnetic field to the magnetoresistive head to be tested and filters the resulting time varying (AC) voltage signal indicative of the resistance of the head with a capacitor to remove the DC component of the signal. The AC component of the signal is then amplified, digitized, and analyzed to obtain the resistance properties of the magnetoresistive head.

Abstract translation: 公开了一种用于测量作为施加到磁头的磁场的函数的磁阻磁头的电阻的测试器。 测试仪对待测试的磁阻头施加时变磁场，并且用电容器滤除产生的表示电阻电阻的时变（AC）电压信号以去除信号的直流分量。 然后对信号的AC分量进行放大，数字化和分析，以获得磁阻头的电阻特性。

公开(公告)号：WO1997017621A1

公开(公告)日：1997-05-15

申请号：PCT/US1996018093

申请日：1996-11-08

Applicant: PHASE METRICS

Inventor： PHASE METRICS ,  INBAR, Michael

IPC: G01R33/12

CPC classification number: G01R33/1207

Abstract: A tester for testing the smoothness of a magnetic disk comprising a magnetic head (14) which can write and read data onto a disk. The magnetic head (14) generates a read signal that corresponds to the magnetic field of the disk. The read signal is a signal which varies at a frequency. When the head (14) strikes an asperity, the contact will produce a mechanical resonance in the head (14) and modulate the frequency of the read signal. The frequency modulated read signal is detected by a phase lock loop circuit (20) which generates an error signal. The error signal is provided to a digital signal processor (36) to measure the magnitude and number of asperities in the disk.

Abstract translation: 一种用于测试磁盘的平滑度的测试器，包括可以将数据写入和读取到磁盘上的磁头（14）。 磁头（14）产生对应于磁盘磁场的读取信号。 读取信号是频率变化的信号。 当头部（14）突起时，触点将在头部（14）中产生机械谐振，并且调制读取信号的频率。 调频读取信号由产生误差信号的锁相环电路（20）检测。 误差信号被提供给数字信号处理器（36）以测量盘中的粗糙度的大小和数量。