Western Digital (fremont), Inc.

Western Digital Technologies, Inc.

Sergey G Muchiyev

Paul Dylan Sherman

Yaw Shing Tang

Cliff C Zhang

Trung Vinh

Rungnapa Dangrungroj

Measurement circuitry is disclosed that is configured to be coupled to a load through a transmission line. A first AC signal having a frequency &#x3c9;is applied to the transmission line and a first input impedance of the transmission line is measured. A second AC signal having a frequency &#x3c9;is applied to the transmission line and a second input impedance of the transmission line is measured, wherein the frequency &#x3c9;is different than the frequency &#x3c9;. A third AC signal having a frequency &#x3c9; is applied to the transmission line and a third input impedance of the transmission line is measured, wherein the frequency &#x3c9; is different than the frequency &#x3c9;and different than the frequency &#x3c9;. A resistance of the load is measured based on the measured first input impedance, the measured second input impedance, and the measured third input impedance.

Measuring a load resistance coupled to a transmission line

A device may be or include a cartridge configured to receive a head gimbal assembly (HGA) of a storage device and electrically connect the HGA to a HGA testing device. The cartridge may include a pre-amplifier configured to be electrically connected with corresponding electrical traces of the HGA and to the HGA testing device; a plurality of probe pins electrically connected to the pre-amplifier and configured to be electrically connected to corresponding electrical traces of the HGA; and a clamper including a dielectric layer and configured to selectively assume an open or closed configuration. In the closed configuration, the plurality of probe pins is electrically connected to corresponding ones of the plurality of electrical traces of the HGA. The clamper, in combination with at least some of the probe pins, forms an electrical filter configured to at least condition signals to and from the pre-amplifier and the HGA.

Pre-amplifier cartridge for test equipment of head gimbal assembly

An apparatus is disclosed comprising control circuitry configured to measure a rotation speed of a disk over multiple revolutions of the disk to generate a measured range of rotation speeds, select a target rotation speed from the measured range of rotation speeds, and when the rotation speed of the disk substantially matches the target rotation speed, enable writing of servo data on the disk using a head.

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Mountain View, CA, United States of America

Sergey G Muchiyev