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In this paper, a SCR(Silicon Controlled Rectifier)-based dual directional ESD protection circuit is proposed. The proposed protection circuit can provide effective protection for ICs against ESD (Electrostatic Discharge) in the both positive and negative directions. To analysis its electrical characteristics, it is verified through the TLP(Transmission Line Pulse) system. Also thermal reliability under high temperature conditions (300K–500K) is verified. In the measurement results, it has trigger voltage of 10.16V and holding voltage of 4.64V. It is shown that the proposed protection circuit has superior characteristics compared to the conventional SCR. In addition, these characteristics make the proposed protection circuit has area efficiency. As a result, the proposed dual directional ESD protection circuit can discharge ESD current in four stress mode (PD, ND, PS, NS) with superior characteristics and reliability.

In this paper, we proposed a novel SCR (Silicon Controlled Rectifier)-based ESD (Electrostatic Discharge) protection circuit for I/O and power clamp. HHVSCR (High Holding Voltage SCR) has a high holding voltage and low trigger voltage characteristics than conventional SCR. And advanced HHVSCR is proposed for high voltage application. These characteristics enable to have latch-up immunity under normal operating conditions as well as superior full chip ESD protection. Proposed ESD protection circuits are verified and compared by TCAD simulation. As a result of simulation, holding voltage increases with different design parameters. The holding voltage of HHVSCR changes from 3V to 4.83V. On the other hands, the holding voltage of Advanced HHVSCR changes from 4.61V to 8.75V. The trigger voltage of HHVSCR has about 8~9V whereas Advanced HHVSCR varies from 27.3V to 32.7V due to different breakdown occurrence.

Reverberation is acoustical distortion which degrades the fidelity and intelligibility of speech signal in a speech recognition system. This paper presents a speech enhancement algorithm using an one-microphone for automatic speech recognition system. The proposed algorithm is based on a simple spectral subtraction. To further improve system performance, we employ a method of Voice Activity Detection (VAD) using spectral entropy.

In this paper, we propose new dereverberation method for underwater speech communication. The speech signal generated by a fixed one source. Then the signal received on 9 horizontal sensor array in shallow water environment. Finally, received signals are processed dereverberation. The received signals achieved delay-and-sum beamforming and then, signals calculates time delay both each signals. Next, we calculate Hilbert envelope using time delay information and LP residuals. At last, we acquire new LP residual combination using various parameters. Proposed technique shows better performance than previous dereverberation technique.

In this paper, we introduce the application of the cooperative diversity in underwater wireless communication. Cooperative diversity creates a virtual sensor array between source and destination, thereby influence the space diversity benefits of multiple-input/multiple-output (MIMO) system. In this paper, we consider the amplify-and-forward (AF) protocols in cooperative diversity for underwater wireless communication. For AF protocol in cooperative diversity, each relay node is amplifying the received signal from the source node and retransmits to destination node. We used the Ray mode model base on underwater channel parameter between each node for assume the underwater channel. Simulation results of the AF cooperative diversity in underwater wireless communication show the better performance than the direct transmission. As a result, we acquired more enhanced result of about 5 dB than other comparison technique.