Peter Ho - Union City CA Graham M. Flower - San Jose CA Richard C. Walker - Palo Alto CA
Assignee:
Agilent Technologies, Inc. - Palo Alto CA
International Classification:
H04J 302
US Classification:
370537, 327407
Abstract:
A multiplexer for use with switching apparatus for data communication networks. The multiplexer topology includes two or more groupings, or sections, each containing a plurality of individual channels. Each of the channels has an input buffer amplifier and an output Ft-doubler circuit. The outputs of all of the channels within a each particular channel section are connected in parallel relation, and fed to respective common-base transistor amplifiers. The outputs of all of the common-base amplifiers for each channel section, in turn, are connected in parallel and fed to the inputs of a pair of emitter-follower amplifiers. Through the use of selectively actuated current sources, each multiplexer channel is normally biased off, unless that channel is selected for a switching operation. Bleeder current sources are applied to the emitters of the common-base amplifiers to reduce output jitter from the channels which are biased off. The multiplexer architecture provides high speed operation from channel sectioning, and low power consumption by reducing both the amount of current drawn and the voltage potential necessary, to operate the multiplexer.
Method, System, And Program For Estimating Coil Resistance Of A Voice Coil Motor In A Disk Drive System
Peter Kui Ho - Morgan Hill CA, US Mantle Man-Hon Yu - San Jose CA, US
Assignee:
Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam
International Classification:
G11B005/596
US Classification:
360 7805
Abstract:
Provided are a method, system, and program for estimating coil resistance of a voice coil motor for an actuator assembly in a disk drive system. An estimation is made of a calibration coil resistance during a calibration operation. A determination is made of a distance moved during a seek operation. The determined distance and the calibration coil resistance are used to estimate a current coil resistance following the seek operation.
Method And Apparatus For Providing A Marker For Adaptive Formatting Via A Self-Servowrite Process
Paul M. Cisewski - Morgan Hill CA, US Blake Finstad - San Juan Bautista CA, US Peter Kui Ho - Morgan Hill CA, US Kishan Kumar Kumbla - Morgan Hill CA, US Daniel J. Malone - San Jose CA, US Scott Arthur Thomas - San Jose CA, US
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G11B 21/02
US Classification:
360 75
Abstract:
A method and apparatus for providing a marker at the end of the adaptive self-servowrite process for adaptive formatting via the self-servowrite process. The mark is used later in the drive manufacturing process to identify the number of tracks written on the surface and thus determine the appropriate format to use in the drive.
Peter Ho - Union City CA, US Benny W. H. Lai - Fremont CA, US
International Classification:
H04L 27/01
US Classification:
375232, 375230, 375371
Abstract:
Equalization for ports of a crosspoint switch at least partially offsets transmission losses such as skin loss. The equalization may be tailored on a port-by-port basis using adaptive equalization or adjustable equalization, but fixed equalization may be used. In some implementations, each input port or output port of a crosspoint switch has a dedicated equalization circuit that has filtering characteristics that are based on the signal characteristics (e. g. , jitter) measured at the affected output port. For an adjustable equalization approach, the adjustable equalization circuitry includes various switched connections that are selectively coupled and decoupled to achieve the target level of equalization.
Disk Drive With Adaptive Actuator Braking Upon Unexpected Power Loss
Peter Kuikong Ho - Morgan Hill CA, US Lee DuyLy Nguyentran - San Jose CA, US Bond-Yen Ting - San Jose CA, US Phong Van Vu - San Jose CA, US
Assignee:
HItachi Global Storage Technologies Netherlands B.V. - Amsterdam
International Classification:
G11B 21/02
US Classification:
360 75
Abstract:
A magnetic recording hard disk drive (HDD) uses adaptive braking of the voice coil motor (VCM) actuator upon unexpected loss of power during a track seek. An adaptive braking controller applies a preselected value of brake voltage to the VCM to reverse the motion of the freely-moving actuator. The value of the selected brake voltage is determined from the actuator velocity. A set of brake voltage values is stored in memory in the HDD, and each brake voltage value corresponds to a band of track seek lengths, with each band representing a range of actuator velocities. For each seek, the value of brake voltage corresponding to the band in which the seek length falls is stored in a register. If emergency power-off (EPO) occurs during the seek, the value of brake voltage is recalled from the register and applied to the VCM to brake the VCM. After the VCM has been adaptively braked in this manner, actuator retract occurs to unload the heads.
Reduced-Crosstalk Wirebonding In An Optical Communication System
Peter Ho - Union City CA, US Michael A. Robinson - Fremont CA, US Zuowei Shen - San Jose CA, US
Assignee:
Avago Technologies Fiber IP (Singapore) Pte. Ltd. - Singapore
International Classification:
H01L 31/075 H01L 31/105 H01L 31/117
US Classification:
257458, 257784, 257786, 438208, 438912
Abstract:
Wirebonds are formed to couple an opto-electronic device chip having two or more opto-electronic devices to a signal processing chip. Two or more mutually adjacent wirebond groups, each corresponding to one of the opto-electronic devices, are formed. For example, each wirebond group can include a first wirebond coupling a P-terminal of the opto-electronic device of the wirebond group to the signal processing chip, a second wirebond coupling an N-terminal of the opto-electronic device of the wirebond group to the signal processing chip, and a third wirebond coupling the opto-electronic device chip to the signal processing chip.
A clock-data recovery circuit includes a phase rotator, a phase detector and a charge pump. The phase rotator receives first and second reference clocks and differential control signals. The phase rotator generates a modified clock signal responsive to the first and second reference clocks and the control signals. The phase detector receives a data signal and the modified clock signal. The phase detector generates a modified data signal and a phase error signal responsive to the data signal and the modified clock signal. The charge pump receives the phase error signal and generates the differential control signals, which direct the phase rotator to interpolate between select clock phases.
Method For Creating On-Package Inductors For Use With Integrated Circuits
Peter Chi-Ming Ho - San Mateo CA D. Douglas Baumann - San Jose CA Sang S. Lee - Sunnyvale CA
Assignee:
VLSI Technology, Inc. - San Jose CA
International Classification:
H01F 706
US Classification:
29605
Abstract:
A method is described for creating an inductor in the package for an integrated circuit. The inductor is formed by utilizing one or more of the bond leads as the core of the inductor and by winding a series of coils about the core in connection either with the bond pads of the integrated circuit itself or to other bond leads for connection outside the integrated circuit chip.