Performance Tendency of Gain and Noise Figure at Different EDFA Configurations

A comprehensive behavioral investigation of gain and noise figure （NF） at different erbium doped fiber amplifier （EDFA） configurations is proposed. Configurations such as single pass （SP）, single pass with filter （SPF）, double pass （DP） and double pass with filter （DPF） are designed, investigated and compared. A continuous increasing of gain value is recorded by changing the configuration from SP to SPF to DP then to DPF. The NF value shows different behaviors at different configurations.

Beam Pattern Design and Performance Analyses for Circular Array with Spherical Baffles

The influence of a rigid spherical baffle on the response of a uniform circular microphone array （UCA） is analyzed and two eigen-beam beamforming arrays are designed in the eigen-beam subspaee derived from the soundfield decomposition. Expressions of white noise gain （WNG） and directivity index （DI） are derived for the designed arrays. Performance analyses are carried out for the designed arrays and compared between those of the delay-and-sum beamforming array using UCA with and without a rigid sphere. Computer simulations demonstrate that the designed arrays have frequency-independent directivity with the cost of reduced robustness at low frequency band. The delay-and-sum beamforming array has constant WNG at all frequencies, while its directivity of which is reduced at low frequency band. The rigid sphere can improve the robustness for all the arrays.

Constrained minimum power combination for broadband beamformer design in the STFT domain

Beamforming using sensor array is widely used in spatial signal processing since it offers better spatial focusing capability than single sensor. However, in practical appli- cations for broadband signal, there always exists a trade-off issue between the directivity capability of an array and its robustness on system errors. In this paper, in order to combine merits of different beamformers instead of trade-off their per- formances, we propose a constrained minimum-power com- bination method. We firstly analyze two optimal beamform- ers that maximize Directivity Factor （DF） and White Noise Gain （WNG） respectively. Then we propose a non-linear combination method, which automatically selects the best beamformer that has the minimum output power, so as to control the unwanted white noise amplification and keep the maximum DF if possible. Two solutions to the proposed com- bination strategy are given. They do not need to determine the correct trade-off factor used in linear combination method, and avoid challenge ~stimations on noise and target statistics required in adaptive beamforming. The performance of the proposed beamformer is evaluated in ideal noise fields and complicated noise fields respectively. It is shown that the proposed beamformer integrates merits of different beamform- ers. It always achieves the best speech quality and biggest noise reduction compared to other popular beamformers.

Reaching a stochastic consensus in the noisy networks of linear MIMO agents:Dynamic output-feedback and convergence rate

This paper addresses the leader-following consensus problem of linear multi-agent systems(MASs) with communication noise. Each agent's dynamical behavior is described by a linear multi-input and multi-output(MIMO) system, and the agent's full state is assumed to be unavailable. To deal with this challenge, a state observer is constructed to estimate the agent's full state. A dynamic output-feedback based protocol that is based on the estimated state is proposed. To mitigate the effect of communication noise, noise-attenuation gains are also introduced into the proposed protocol. In this study, each agent is allowed to have its own noise-attenuation gain. It is shown that the proposed protocol can solve the mean square leader-following consensus problem of a linear MIMO MAS. Moreover, if all noise-attenuation gains are of Q(t-β), where b∈(0,1), the convergence rate of the MAS can be quantitatively analyzed. It turns out that all followers' states converge to the leader's state in the mean square sense at a rate of O(t-β).

A low power 2.4 GHz transceiver for ZigBee applications

This paper presents a low power 2.4 GHz transceiver for ZigBee applications.This transceiver adopts low power system architecture with a low-IF receiver and a direct-conversion transmitter.The receiver consists of a new low noise amplifier（LNA） with a noise cancellation function,a new inverter-based variable gain complex filter （VGCF） for image rejection,a passive quadrature mixer,and a decibel linear programmable gain amplifier（PGA）. The transmitter adopts a quadrature mixer and a class-B mode variable gain power amplifier（PA） to reduce power consumption.This transceiver is implemented in 0.18μm CMOS technology.The receiver achieves—95 dBm of sensitivity,28 dBc of image rejection,and -8 dBm of third-order input intercept point（IIP3）.The transmitter can deliver a maximum of＋3 dBm output power with PA efficiency of 30%.The whole chip area is less than 4.32 mm^2. It only consumes 12.63 mW in receiving mode and 14.22 mW in transmitting mode,respectively.