Kyeongho Lee

US Patent:

6657498, Dec 2, 2003

Filed:

Jul 17, 2002

Appl. No.:

10/196136

Inventors:

Joonbae Park - San Jose CA
Seung-Wook Lee - San Jose CA
Won-Seok Lee - San Jose CA
Kyeongho Lee - San Jose CA

Assignee:

GCT Semiconductor, Inc. - San Jose CA

International Classification:

H03G 310

US Classification:

330285, 330278

Abstract:

A variable gain, low noise amplifier is described, which is suitable as the input amplifier for a wireless terminal, or as the pre-amplifier stage of a wireless terminal transmitter. The amplifier may achieve variable gain by deploying a network of transistors in a parallel array, each independently selectable by a PMOS switch, and providing the variable resistance for the resonant circuit. Power dissipation can also be mitigated by using a network of driving transistors, each independently selectable by a PMOS switch. The resonant frequency of the amplifier may be made tunable by providing a selection of optional pull-up capacitors.

US Patent:

6876266, Apr 5, 2005

Filed:

May 23, 2003

Appl. No.:

10/443835

Inventors:

Yido Koo - San Jose CA, US
Jeong-Woo Lee - San Jose CA, US
Joonbae Park - San Jose CA, US
Kyeongho Lee - San Jose CA, US

Assignee:

GCT Semiconductor, Inc. - San Jose CA

International Classification:

H03B005/00

US Classification:

331117R, 331117 FE, 331167, 331 36 C, 331185, 331177 V, 331177 R, 331175

Abstract:

A voltage-controlled oscillator including an active oscillator circuit, an inductor, and capacitive circuits is disclosed. The capacitive circuits are selectively turned on and off to control the frequency of the voltage-controlled oscillator. Particularly, the inductor and the capacitors in the capacitive circuits form LC circuits that provide feedback to the active oscillator circuit. To avoid damage to the switches in the capacitive circuits, the capacitive circuits further comprise resistors. The resistors can be configured in several different ways so that the voltage-controlled oscillator can have a high degree of reliability, and a wide tuning range with constant phase noise performance.

US Patent:

20030045264, Mar 6, 2003

Filed:

Aug 28, 2002

Appl. No.:

10/229267

Inventors:

Joonbae Park - San Jose CA, US
Kyeongho Lee - san Jose CA, US

International Classification:

H04B001/16

US Classification:

455/323000, 455/334000

Abstract:

The present invention is directed to a linearization apparatus and method. Preferred embodiments according to the present invention can combine an auxiliary non-linear block to a functional block of a system to increase linearity of an output signal of the system such as a communication system. System overhead due to the non-linear auxiliary block can be small because of circuit structure, cost and low consumption. Further, the non-linear auxiliary block can be designed so that no feedback path is required. Further preferred embodiments can use a feedback path without loss of stability by using a cancellation apparatus or process based on an averaging detection of the output signal. For example, a feedback loop can detect power leakage in a sideband caused by non-linearities of the communication system.