Li Liu

US Patent:

6569638, May 27, 2003

Filed:

Mar 3, 2000

Appl. No.:

09/517734

Inventors:

I. Bernard Weinstein - Englewood NJ
W. Joseph Thompson - Doylestown PA
Jae-Won Soh - Cliffside Park NJ
Li Liu - Ambler PA
Han Li - Yardley PA

Assignee:

Cell Pathways, Inc - Horsham PA

International Classification:

C12Q 148

US Classification:

435 15, 435 692, 435184

Abstract:

This invention provides a method to identify compounds potentially useful for the treatment and prevention of neoplasia in mammals. The phosphodiesterase inhibitory activity of a compound is determined along with its ability to elevate JNK kinase activity. Growth inhibitory and apoptosis inducing effects on cultured tumor cells are also determined. Compounds that exhibit phosphodiesterase inhibition, an ability to elevate JNK kinase activity, growth inhibition and apoptosis induction are desirable for the treatment of neoplasia.

US Patent:

7154670, Dec 26, 2006

Filed:

Mar 10, 2004

Appl. No.:

10/796930

Inventors:

Hongbin Zhang - Marlboro NJ, US
Li Liu - Carneys Point NJ, US
R. Brian Jander - Freehold NJ, US
Alexei N. Pilipetskii - Colts Neck NJ, US

Assignee:

Tyco Telecommunications (US) Inc. - Morristown NJ

International Classification:

G02B 27/28

US Classification:

359501, 359497, 385 11

Abstract:

Methods and apparatus of performing polarization control for optical transmissions. The methods and apparatus enable polarization control devices to achieve a desired output state of polarization regardless of the input state of polarization. The desired state of polarization can be achieved by rotating waveplates in a polarization controller in a sequential fashion. Each waveplate may be continually adjusted or dithered so long as the feedback signal satisfies a feedback condition. Once the feedback signal exceeds the feedback condition, the next waveplate in the polarization controller is adjusted. This enables the methods and apparatus to rapidly adjust the state of polarization away from dead spots and minimize loss control problems.

US Patent:

7656229, Feb 2, 2010

Filed:

Jan 28, 2008

Appl. No.:

12/021061

Inventors:

Junxiong Deng - San Diego CA, US
Li Liu - San Diego CA, US
Prasad S. Gudem - San Diego CA, US

Assignee:

QUALCOMM, Incorporated - San Diego CA

International Classification:

H03F 3/38

US Classification:

330149, 375296

Abstract:

An electronic device includes an amplifier circuit coupled to a linearizer. The amplifier circuit may receive a first input signal including first and second frequencies and generate a first output signal including a delta frequency signal at a delta frequency, which is the difference between the first frequency and the second frequency. The linearizer includes a signal detector circuit, a current-mirror circuit, a low pass filter, a phase shifter, and a bias circuit. The signal detector circuit may generate a second output signal. The current-mirror circuit may adjust an amplitude of a signal. The low pass filter may eliminate a portion of the second output signal having frequencies greater than the delta frequency. The phase shifter may generate a feedback signal corresponding to the delta frequency signal. An amplitude and/or a phase of the feedback signal is different from an amplitude and/or a phase of the delta frequency signal.

US Patent:

7692486, Apr 6, 2010

Filed:

Oct 5, 2007

Appl. No.:

11/868159

Inventors:

Mahim Ranjan - La Jolla CA, US
Li Liu - San Diego CA, US

Assignee:

QUALCOMM, Incorporated - San Diego CA

International Classification:

H03F 1/08

US Classification:

330 86, 330293, 330291

Abstract:

An amplifier is disclosed that includes configurable feedback based on the output of a received signal strength indicator. The feedback may be increased for high received signal levels, and decreased for low received signal levels. In an embodiment, the configurable impedance may comprise a plurality of discrete impedance settings. Amplitude and/or time hysteresis may be incorporated.

US Patent:

8035447, Oct 11, 2011

Filed:

Aug 21, 2007

Appl. No.:

11/842712

Inventors:

Li Liu - San Diego CA, US
Prasad S. Gudem - San Diego CA, US

Assignee:

QUALCOMM, Incorporated - San Diego CA

International Classification:

H03F 1/26

US Classification:

330149, 330254

Abstract:

Active circuits with active loads linearized via distortion cancellation are described. In one design, an apparatus includes a first stage and a load stage. For an amplifier, the first stage amplifies an input signal and provides an output signal having a larger signal level. For a mixer, the first stage mixes an input signal with an LO signal and provides an output signal. The load stage provides an active load for the first stage and is linearized by canceling distortion generated by the active load. In one design, the load stage includes a first transistor that provides the active load and generates distortion due to its nonlinearity. The load stage further includes at least one transistor that generates a replica of the distortion from the first transistor. The distortion replica is used to cancel the distortion from the first transistor. The first stage may also be linearized with distortion cancellation.

US Patent:

8253506, Aug 28, 2012

Filed:

Oct 5, 2010

Appl. No.:

12/897918

Inventors:

Li Liu - San Diego CA, US
Chiewcharn Narathong - San Diego CA, US

Assignee:

QUALCOMM, Incorporated - San Diego CA

International Classification:

H03C 3/22
H03L 1/02

US Classification:

331177V, 331 36 C, 331117 R, 331176

Abstract:

A resonator of a VCO includes a fine tuning main varactor circuit, an auxiliary varactor circuit, and a coarse tuning capacitor bank circuit coupled in parallel with an inductance. The main varactor circuit includes a plurality of circuit portions that can be separately disabled. Within each circuit portion is a multiplexing circuit that supplies a selectable one of either a fine tuning control signal (FTAVCS) or a temperature compensation control signal (TCAVCS) onto a varactor control node within the circuit portion. If the circuit portion is enabled then the FTAVCS is supplied onto the control node so that the circuit portion is used for fine tuning. If the circuit portion is disabled then the TCAVCS is supplied onto the control node so that the circuit portion is used to combat VCO frequency drift as a function of temperature. How the voltage of the TCAVCS varies with temperature is digitally programmable.

US Patent:

8294528, Oct 23, 2012

Filed:

Dec 28, 2010

Appl. No.:

12/979659

Inventors:

Guansheng Li - San Diego CA, US
Li Liu - San Diego CA, US
Yiwu Tang - San Diego CA, US

Assignee:

Qualcomm Incorporated - San Diego CA

International Classification:

H03B 5/12
H03K 3/30
H03C 3/22

US Classification:

331117FE, 331 36 C, 331 36 L, 331 76, 331112, 331177 V

Abstract:

A VCO includes a transformer-based resonator that has a first LC tank and a second LC tank. The resonator has an even resonant mode and an odd resonant mode. The VCO further includes an active transconductance network that is coupled to a two-terminal port of the first tank and is also coupled to a two-terminal port of the second tank. A first terminal of the port of the first tank is capacitively coupled to a first terminal of the port of the second tank. A second terminal of the port of the first tank is capacitively coupled to a second terminal of the port of the second tank. The active transconductance network causes the resonator to resonate in a selectable one of the even and odd resonant modes depending on a digital control signal. The VCO is fine tuned by changing the capacitances of capacitors of the tanks.

US Patent:

8433272, Apr 30, 2013

Filed:

Sep 18, 2008

Appl. No.:

12/233420

Inventors:

Prasad S. Gudem - San Diego CA, US
Jose Cabanillas - San Diego CA, US
Li-Chung Chang - Irvine CA, US
Li Liu - San Diego CA, US

Assignee:

Qualcomm Incorporated - San Diego CA

International Classification:

H04K 3/00
H04B 1/06
H04B 7/00

US Classification:

4552341

Abstract:

A receiver includes a jammer detector configured to detect the presence or the absence of jamming in a communication signal within a gain state. The receiver further includes an amplifier configured to amplify the communication signal in a high linearity receiving mode or a low linearity receiving mode, wherein the high linearity receiving mode corresponds with a lower gain for the gain state in the amplifier relative to that of the low linearity receiving mode. In addition, the receiver includes a processing unit coupled to the jammer detector, the processing unit being configured to control the amplifier to amplify the communication signal in either the high linearity receiving mode or the low linearity receiving mode, based on the output of the jammer detector detecting the presence or the absence of jamming in the communication signal. A method is also provided for processing a communication signal in a receiver.