Design and Analysis of Analog to Digital Converter System Clock Source Using Direct Digital Synthesizer

A requirement of multiple format standards by mobile telecommunication (GSM, CDMA, WCDMA, and TD-SCDMA) test set needs to be delivered possibly at lower cost. As to support its capability, phase-locked loop (PLL) frequency synthesizer has been designated as an essential part in most of the design within the box. The old design may be bulky and subject to many issues with the components’ variation and aging effect. In recent years, the direct digital synthesizer (DDS) has been popularly in used to replace the PLL architecture. This chapter will focus on the DDS selection, architecture topology, prototyping, implementation technique with both hardware and software, and performance as a clock source to a sampled system as referred to receiver interest. The key parameters in the sampled system greatly rely on the jitter and phase noise specification. If they are not properly defined, the overall signal-to-noise ratio (SNR) at the sampled system output will be impacted. Eventually the receiver quality will be degraded and resulted in tremendous loss. Thus, a proper reconstruction filter design will be delivered to ensure the jitter and phase noise performance is met without degrading the existing specification by taking accountability into the matching characteristic and signal integrity

Time of arrival estimation using fast Fourier transform overlap for underwater distance measurement

1070-1080This paper presents an underwater acoustic distance measurement system based on Fast Fourier Transform (FFT) overlap. The low-cost underwater communication device is developed to achieve the objective. The time-of-arrival (TOA) technique is used to estimate the distance between the transmitter and receiver. The TOA estimation is derived based on the intensity of the received signal with frequency of interest. The extraction of the signal from the receiver is performed by using digital signal processing algorithms. FFT is used to convert the receiving signal from time domain into frequency domain for extracting the information of signal (relevant frequency and amplitude). Hence, TOA estimation can be obtained from the frequency information using overlap transform processing. This enables the increase of the TOA measurement resolution with the overlap technique. Trilateration algorithm is also employed as to determine the relative position of underwater target based on distance measurement. This approach is tested on shallow underwater to estimate the position of target. The experimental results are presented to demonstrate its capabilities

Modeling And Identification Of An Underwater Glider.

Underwater gliders are type of autonomous underwater vehicle that glide by controlling their buoyancy and attitude using internal actuators

Performance Measure Of Some Subspace-Based Methods For Closed-loop System Identification.

This paper presents some of the methods under subspace-based family to perform closed-loop system identification. Three methods have been observed; those are the ORT method, MOESP method and CCA method

Robust nonlinear control of a buoyancy-driven airship system using backstepping integral sliding mode control

This paper presents the development of nonlinear robust control based on backstepping and sliding mode control system to control a longitudinal plane of a new concept of airship. Nature of autonomous airship is non-rigid body, very nonlinear and therefore control strategy can be used to accommodate the nonlinearities in the airship model. The performance of the proposed controller is simulated using MATLAB/Simulink software which tested for nominal system, system with external disturbance and system with parameter variation to evaluate its robustness against external disturbance and parameter variations. The controller is designed for the gliding path from 10° downward to 10° upward. The performance of proposed controller is compared against the performance of backstepping sliding mode control and integral sliding mode control in terms of chattering reduction and steady state error. The simulation results have shown that the proposed controller has improved the output tracking performance around 25% better as compared to lowest performance of integral sliding mode and the undesired chattering in control input and sliding surface has been reduced almost 100%

Analysis of Cumulative Distribution Function of 2-year Rainfall Measurements in Ogbomoso, Nigeria

Abstract: The conversion of most available hourly rainfall data to 1-minute integration time rain rate statistic is imperative for accurate estimation of attenuation due to rain employed in the design of both terrestrial and earth-to-space microwave systems. 2-year rainfall data collected at Ogbomoso, South-west region of Nigeria, between the periods of 2009 and 2010 was used in the analysis. Result shows that a power law relationship exists between the equiprobable rain rates of two different integration times. The regression coefficients a and b obtained are slightly different from the ITU-R recommendation. The conversion factor obtained at Ogbomoso is lower compared to Ile-Ife, in the South-west region of the country. The disagreement is attributed to the effect of global warming hitting the whole universe most especially the tropical regions. This study also reveals that different conversion factors are required for different locations even within the same climatic region

Review of sliding mode control application in autonomous underwater vehicles

973-984This paper presents a review of sliding mode control for autonomous underwater vehicles (AUVs). The AUVs are used under water operating in the presence of uncertainties (due to hydrodynamics coefficients) and external disturbances (due to water currents, waves, etc.). Sliding mode controller is one of the nonlinear robust controllers which is robust towards uncertainties, parameter variations and external disturbances. The evolution of sliding mode control in motion control studies of autonomous underwater vehicles is summarized throughout for the last three decades. The performance of the controller is examined based on the chattering reduction, accuracy (steady state error reduction), and robustness against perturbation. The review on sliding mode control for AUVs provides insights for readers to design new techniques and algorithms, to enhance the existing family of sliding mode control strategies into a new one or to merge and re-supervise the control techniques with other control strategies, in which, the aim is to obtain good controller design for AUVs in terms of great performance, stability and robustness

Automated Printed Circuit Board Assembly Verification and Validation System

With the fast-paced evolution in the engineering field especially in electronics, the design of circuitry is becoming more and more complex. Hence, to make sure the Printed Circuit Board Assembly (PCBA) is designed correctly, the prototypes of the PCBA have to be tested and validated before moving on to manufacturing and production process. The InCircuit Test (ICT) and flying probes are too expensive to be applied for a prototype stage. Hence, the verification and validation (V&V) test for the prototype of PCBA is done manually by the V&V engineers. However, it is a complex and time-consuming process. Therefore, there is a requirement to improve the current PCBA prototype verification and validation. This project is proposed to assist V&V engineers to perform a V&V test for PCBA prototype. This project basically consists of a CNC machine, which has total five degrees of freedom with measuring probe at the end effector. Three stepper motors were used to move the x, y and z coordinate of the probe. The stepper motors were controlled by controller myRIO with stepper motor driver A4988. Besides that, another two smaller stepper motors were used for the probing mechanism. The probing mechanism was designed and simulated by using SolidWorks software. For software, the data extraction from the PCB file was done by the algorithm built using LabVIEW. In addition, a graphical user interface (GUI) was also designed and built using LabVIEW. The system was tested in terms of accuracy and consistency by using samples of PCB. The results from the evaluation showed about 70.83% of accuracy in average. Overall, the performance of the system is acceptable and the accuracy of the system can be improved by the implementation of closed-loop control into the system

Nonlinear robust integral sliding super-twisting sliding mode control application in autonomous underwater glider

1016-1027The design of a robust controller is a challenging task due to nonlinear behaviour of the glider and surround environment. This paper presents design and simulation of nonlinear robust integral super-twisting sliding mode control for controlling the longitudinal plane of an autonomous underwater glider (AUG). The controller is designed for trajectory tracking problem in existence of external disturbance and parameter variations for pitching angle and net buoyancy of the longitudinal plane of an AUG. The algorithm is designed based on integral sliding mode control and super-twisting sliding mode control. The performance of the proposed controller is compared to original integral sliding mode and original super-twisting algorithm. The simulation results have shown that the proposed controller demonstrates satisfactory performance and also reduces the chattering effect and control effort

Depth and pitch control of USM underwater glider: performance comparison PID <i style="">vs.</i> LQR

200-206Present study consists the design of an optimal state feedback controller for our USM Underwater Glider (USM-Glider). The glider mathematical model for motion control is obtained using MATLAB System Identification Toolbox, where ballast pumping rate is an input signal to the system. Different parameters were observed independently, the pitching angle, and the depth. Two different models were obtained for the respective observations that relates ballast pumping rate to pitching angle and depth. From the transfer obtained, we apply a Linear Quadratic Regulator (LQR) and PID control schemes to observe the performance of the controllers over the pitching angle, and the depth. The optimal performances are obtained via tuning of Qs and Rs matrices of the LQR and gain of Kp, Ki and Kd of the PID controller. The results show both controllers provide satisfactory performance