Alpha Imaging Technology Corporation

Via Technologies, Inc.

Chih-Chia Wang

Chingwo Ma

Shu-Mei Li

Kai-Pon Kao

Hsin-Chin Hsu

Cen-Chieh Huang

Yi-Sheng Lin

A null detector and its corresponding method are provided. The null detector includes a power detector, a smoother, and an overlapper. The power detector outputs a power level signal according to the power level of a received signal. The smoother is coupled to the power detector for determining according to the power level signal whether the received signal is transmitting a null symbol, and then the smoother outputs a null detection signal at a first state value or a second state value indicating the result of the determination. The overlapper is coupled to the smoother for providing the duration and position of the null symbols transmitted by the received signal according to the null detection signal.

Null detector and method thereof

A time domain symbol timing synchronization circuit is disclosed, which comprises: an autocorrelation function calculator for calculating cyclic prefix autocorrelation functions and an offset time estimator for searching peak positions of cyclic prefix autocorrelation functions to indicate symbol boundary of received communication symbols. The offset time estimator compares a current peak position and a previous peak position. If (a) the difference of the positions is larger than a threshold and (b) the current peak is smaller than a reference average peak, the current peak is determined as false; the offset time estimator weeds out and replaces the current peak position by the previous peak position; and the current peak is not introduced in the reference average peak calculation.

Time domain symbol timing synchronization circuit and method thereof for communication systems

An Automatic Gain Control (AGC) method and system thereof. The power of a detected signal is first checked to ensure that it is large enough for AGC process. A power average of the detected signal is computed and compared to a first threshold in order to determine whether to proceed with a coarse tune procedure or enter a fine tune procedure. Both Low Noise Amplifier (LNA) gain and Variable Gain Amplifier (VGA) gain are tuned during coarse tune, whereas only the VGA gain is tuned during fine tune. The LNA and VGA gains are tuned to predetermined values during coarse tune, and the VGA gain is adjusted according to a difference between a computed average of power and a second threshold.

Automatic gain control for a WLAN system

Growing community of inventors

Taichung, Taiwan

Chih-Chia Wang