Hong Jiang

US Patent:

6445752, Sep 3, 2002

Filed:

Feb 12, 1999

Appl. No.:

09/248904

Inventors:

Hong Jiang - Montclair NJ
Paul L. Palmieri - New Providence NJ
Agesino Primatic, Jr. - Frenchtown NJ
Lesley J. Wu - Parsippany NJ
Liangkai Yu - New Providence NJ

Assignee:

Agere Systems Guardian Corp. - Miami Lakes FL

International Classification:

H04L 2714

US Classification:

375326, 375235

Abstract:

A phase tracker receives a signal component x and forms a phase- and gain-corrected signal z. In particular, the phase tracker performs a Hilbert transform of x to produce a quadrature phase component y to form the constellation defined by (x , y ). Consequently, phase rotation and gain adjustment are combined into a linear transform of the constellation defined by (x , y ). The linear transform z =x +y employs two coefficients and. The coefficients and of the linear transform are derived so as to provide an optimal solution according to minimum mean square error. Approximations to the coefficients and of the linear transform may be iteratively determined with a stochastic gradient method. Advantages of employing the phase- and gain-corrected signal z as an I-phase detection result of a demodulator include 1) the phase rotation and gain adjustment are combined into one operation, and 2) the a sine/cosine lookup table is not employed. Including both phase rotation and a gain adjustment may provide for better performance of the demodulator.

US Patent:

6538832, Mar 25, 2003

Filed:

Jun 7, 2000

Appl. No.:

09/589429

Inventors:

Indumini W. Ranmuthu - Plano TX
Hong Jiang - Plano TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 509

US Classification:

360 46, 360 67, 360 63

Abstract:

In hard disk drives (HDD), a magnetic read head moves over a portion of the hard disk when reading data. A preamplifier, having an initial amplification stage of the single ended type, connects to the magnetic read head and amplifies a data signal picked up by the magnetic read head. The preamplifier typically has multiple read heads, or channels. In order to reduce noise coming into the read channels of the preamplifier from the substrate capacitances of the input transistors connected to the read heads, the input transistors are grouped together into multiple banks that are multiplexed, or turn on separately. To further aid noise reduction, the poles of the single ended amplifier are matched, that is, the frequency response of the constant voltage side is matched to the frequency response to the signal side. This effectively reduces both ground noise and Vcc power supply noise as the the noise becomes common mode on the inputs to a differential amplifier that is connected to the single ended amplifier. Noise is further minimized by connecting the substrates of the switching transistors connected to the input transistors to magnetic read ground, as opposed to integrated circuit ground.

US Patent:

6621649, Sep 16, 2003

Filed:

Nov 10, 2000

Appl. No.:

09/709699

Inventors:

Hong Jiang - Plano TX
Indumini Ranmuthu - Plano TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 502

US Classification:

360 67, 360 46

Abstract:

The present invention relates to a preamplifier circuit comprising a plurality of amplifier stages coupled together and operable to consecutively amplify a signal associated with a head of a hard disk drive. The preamplifier circuit further comprises a power delivery circuit operably coupled to the amplifier stages and operable to provide power to the amplifier stages in a substantially concurrent manner when the hard disk drive is transitioning from a write state to a read state. In addition, the circuit comprises a control circuit operably coupled to the amplifier stages, and operable to activate at least two of the plurality of amplifier stages in a generally consecutive manner after the providing of power to the amplifier stages. In the above manner a saturation of an output of the preamplifier circuit is avoided by preventing substantially a propagation of glitches through the preamplifier circuit and providing for a substantially fast write-to-read transition time.

US Patent:

6687064, Feb 3, 2004

Filed:

Jul 21, 2000

Appl. No.:

09/621107

Inventors:

Hong Jiang - Plano TX
Paul Merle Emerson - Murphy TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 509

US Classification:

360 31, 360 68, 360 46, 369 5342, 340652

Abstract:

A circuit ( ) and method for detecting faults of a write head ( ) of a hard-disk drive system ( ). A first resistor R and a second resistor R are coupled to coil L of write head ( ). A transistor Q is coupled to a common node of resistor R and R. Current I is applied to the coil L, and voltages V and V across the nodes at either end of resistors R and R are analyzed in order to detect faults on write head coil L. The detection is performed during a quiet mode of the hard-disk drive system ( ), so the fault detection is frequency-independent. Open faults are distinguishable from short-to-ground faults by the write fault detection circuit ( ).

US Patent:

6690659, Feb 10, 2004

Filed:

Jan 10, 2000

Appl. No.:

09/480025

Inventors:

Walid Ahmed - Eatontown NJ
Bharat Tarachand Doshi - Holmdel NJ
Hong Jiang - Westfield NJ
Pantelis Monogioudis - Edison NJ
Kiran M. Rege - Marlboro NJ

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

H04Q 700

US Classification:

370328, 370352, 455432

Abstract:

In an IP addressing aspect of the invention, a method for use in an Internet Protocol (IP) based communications system, comprises the steps of: (i) assigning a temporary location IP address (e. g. , LIPA) to a mobile user station in the communications system, the address being a combination of an identifier of the mobile user station (e. g. , MID) and an identifier of a network node in the communications system with which the mobile user station is currently associated (e. g. , RID); and transferring packets to and from the mobile user station in accordance with the temporary location IP address. The method may further comprise the step of changing the temporary location IP address assigned to the mobile user station when the station becomes associated with another network node of the communications system, the changed address being a combination of the identifier of the mobile user station and an identifier of the new network node. The method may further comprise the step of assigning a location IP address to a network node in the communications system, the address being a combination of an identifier of the network node and a common identifier of mobile user stations in the communications system.

US Patent:

6707629, Mar 16, 2004

Filed:

Jun 30, 2000

Appl. No.:

09/608896

Inventors:

Hong Jiang - Plano TX
Paul Merle Emerson - Murphy TX
Bryan E. Bloodworth - Irving TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 509

US Classification:

360 67, 360 68

Abstract:

A digital temperature monitor (DTM ( ) includes a proportional-to-absolute temperature (PTAT) sensor ( ) and reference circuit ( ) coupled to the inputs of a comparator ( ). The DTM ( ) monitors the temperature of adjacent and/or proximate integrated circuitry. The method includes the steps of providing a reference signal to the comparator ( ), increasing the reference signal voltage, and determining the temperature of an integrated circuit by determining when the reference signal is greater than the PTAT sensor ( ) output voltage. The DTM ( ) may be implemented as part of a hard-disk drive preamplifier circuit ( ).

US Patent:

6724556, Apr 20, 2004

Filed:

Jun 29, 2001

Appl. No.:

09/896387

Inventors:

Indumini W. Ranmuthu - Plano TX
Hong Jiang - Santa Clara CA

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 503

US Classification:

360 66, 360 67, 360 46

Abstract:

A differential circuit to read differential data from a disk by a voltage bias includes a read circuit having a read circuit pole to read the differential data from the disk by maintaining the voltage bias and a feedback circuit having a feedback pole to sense deviations in the voltage and to adjust the voltage in response to the deviations. The read circuit pole is separated from the feedback pole in frequency.

US Patent:

6735202, May 11, 2004

Filed:

Jan 10, 2000

Appl. No.:

09/480022

Inventors:

Walid Ahmed - Eatontown NJ
Bharat Tarachand Doshi - Holmdel NJ
Hong Jiang - Westfield NJ
Pantelis Monogioudis - Edison NJ
Kiran M. Rege - Marlboro NJ

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

H04L 1228

US Classification:

370392, 370394, 370401

Abstract:

In a mobility management aspect of the invention, several unique mobility management control messages are defined for use in performing various mobility management functions in the communications system with respect to the mobile user stations and network nodes. These messages may comprise: (i) a Location Update Message (LUM); (ii) a Location Confirm Message (LCM); (iii) a Location Query Message (LQM); (vi) a Location Reply Message (LRM); (v) a Registration Message (RM); and (vi) a Registration Reply Message. One or more of these messages are used in the IP-based system to perform mobility management functions such as location management, mobile access and in-call mobility management.