Essa Jafer

Design and simulation difference types CMOS phase frequency detector for high speed and low jitter PLL

This paper presents the different design schemes of the phase frequency detector (PFD) and compares the output simulation results. The circuits that have been considered are the standard CMOS (S/spl I.bar/PFD), true single-phase clock PFD (TSPC/spl I.bar/PFD), DCVSL differential cascode voltage switch logic PFD (DCVSL/spl I.bar/PFD) and current mode logic PFD (CML/spl I.bar/PFD). The simulation results are focused on exploring the dead zone, high frequency operation, power dissipation and phase noise of the different PFD. The results reported in this paper based on simulation done using SpectreS extracted layout. The different circuits of PFD are designed using 0.35 /spl mu/m CMOS technology with 3.3V supply voltage.

Development of a Wireless Pressure Measurement System Using Interdigitated Capacitors

Remote pressure monitoring is of particular importance in medical and environmental applications as it is less labour intensive, safer and offers peace of mind to the general public. To meet this demand, a prototype system has been developed and used to evaluate thick-film pressure sensors with an oxide dielectric layer. The circuit is based on the principle of capacitance-frequency-voltage conversion and has been designed to minimize power consumption. Each device was tested under hydrostatic pressure in the range 0-17 kPa and assessed in terms of sensitivity, hysteresis, repeatability, creep and temperature effects. The results show that this approach may be used for the fabrication of cost effective, reliable devices for wireless pressure sensing applications

Testing FPGA based digital system using XILINX ChipScope logic analyzer

This paper presents the use of Xilinx ChipScopetrade Pro integrated logic analyzer for Field programmable gate arrays (FPGA) as a board-and system-level diagnostic tool. FPGA designs have become increasingly dense and complex. They are difficult to debug because more and more of the relevant signals are buried deep within the logic fabric. Access to signals in the FPGA, on board or in the system is very restricted whether troubleshooting is done in the lab or in the field. The Xilinx ChipScopetrade Pro integrated logic analyzer has solved much of the problem at the FPGA level. In this work, ChipScopetrade has been used to test and verify a developed system that presents the digital core of a wireless sensor module and it has been implemented in (Spartan 3) based FPGA development board.

A review of low‐power wireless sensor microsystems for biomedical capsule diagnosis

The development of a sensor microsystems containing all the components of data acquisition system, such as sensors, signal‐conditioning circuits, analog‐digital converter, interface circuits and embedded microcontroller (MCU), has become the focus of attention in many biomedical applications. A review of the microsystems technology is presented in this paper, along with a discussion of the recent trends and challenges associated with its developments. A basic description of each sub‐system is also given. This includes the different front end, mixed analog‐digital, power management, and radio transmitter‐receiver circuits. These sub‐system designs are presented and discussed in a comparative study and final remarks are made. The performance of each sub‐system is assessed regarding many aspects related to the overall system performance.

Low‐power wireless smart data acquisition system for monitoring pressure in medical application

Purpose – To develop a wireless sensor micro‐systems containing all the components of data acquisition system, such as sensors, signal‐conditioning circuits, analog‐digital converter, embedded microcontroller unit (MCU), and RF communication modules. This has now become the focus of attention in many biomedical applications.Design/methodology/approach – The system prototype consists of miniature FSK transceiver integrated with MCU in one small package, chip antenna, and capacitive interface circuitry based on Delta‐sigma modulator. At the base station side, an FSK receiver/transmitter is connected to another MCU unit, which send the received data or received instructions from a PC through a graphical user interface GUI. Industrial, scientific and medical band RF (433 MHz) was used to achieve half duplex communication between the two sides. A digital filtering has been used in the capacitive interface to reduce noise effects forming capacitance to digital converter. All the modules of the mixed signal syst...

A Wireless Sensor Network System for Pressure and Temperature Signals Monitoring

In this work, a design of wireless system for multi- sensors monitoring has been presented. The main purpose of this research is to develop an efficient telemetry system for measuring water pressure and temperature signals. The system reads data from two types of sensors, resistive and capacitive. Anderson circuit configuration has been used for the resistive sensor, since it offers linear like behavior. The capacitive interface is based on capacitance-frequency-voltage conversion that uses phase lock loop (PLL) to convert the frequency to voltage. A developed pressure sensors based on polyvinylidene fluoride (PVDF) was used to evaluate the performance of the capacitive interface. Two mechanisms have been adopted to reduce the overall power consumption. These are power scheduling and wakeup circuit for the capacitive interface. The first one is implemented fully by the micro-controller unit (MCU) in order to switch on/off all the system units. A wakeup circuit has been designed to interrupt the MCU when it is in the sleep mode and the capacitive samples are changing significantly. A platform for wireless sensor network (WSN) has been developed so that the receiver side can communicate with more than one sensor node.

Improved charge pump for reduced clock feed through and charge sharing suppression

The design and simulation of an improved charge pump structure has been proposed in this paper to reduce the phase noise of phase locked loop (PLL). The nonideal effects of the charge pump such as the clock feed through, current mismatch and charge sharing are analyzed. The improved and conventional charge pumps are simulated and compared. The charge pump has been designed using 0.35/spl mu/m TSMC technology and the simulation results is obtained by SPECTRES software.

Modeling and simulation of a wireless sensor data acquisition system using PCM algorithms

This work presents a novel simulated model for a wireless data acquisition system. The system reads analogue information provided by two sensors and can be used for medical purposes. Real data has been obtained and a simulation of the two signals coming from both pH and pressure sensors embedded in the system has been employed. The created model contains four main units simulated using SIMULINK. At the first unit, the output signal is encoded to digital signal based on adapting one of the pulse coding modulation (PCM) algorithms. The second unit simulates the processor function that is responsible for framing, mixing and compressing the incoming bit streams from both sensors. The third unit, where the digital data is modulated and sent through different noisy channels, represents an efficient FSK transmitter/receiver model. At the receiver end, the signal is demodulated and processed inversely to extract the original analogue signal read by the two sensors. In this work, the performances of the systems using different PCM methods are studied comparatively in order to control the transmission and reduce the amount of data sent. This leads to a significant reduction in power consumption. In addition, efficiency of the RF channel in terms of bit error rate (BER) and through different noisy conditions is investigated.

Modelling and simulation of a wireless microsensor data acquisition system using PCM techniques

Abstract This paper presents a review of developed simulated models for a wireless data acquisition system. The system reads analogue information provided by two sensors used for medical purposes. The real data have been recorded by two, pH and pressure sensors used in diagnosing conditions of the esophagus that are employed to examine the system performance. The created model contains four main simulated units using SIMULINK. The first unit contains the output signal, which is encoded to digital signal based on adapting one of the pulse coding modulation (PCM) algorithms. The second unit simulates the processor function that is responsible for framing, mixing and compressing the incoming bit streams from both sensors. The third unit, where the digital data are modulated and sent through different noisy channels, represents an efficient FSK transmitter/receiver model. At the receiver end, the signal is demodulated and processed inversely to extract the original analogue signal read by the two sensors. In this work, the performance of the systems using different PCM methods will be studied comparatively in order to control the transmission and reduce the amount of data frames sent. This will lead to a significant reduction in power consumption. In addition, the performance of the RF unit through additive White Gaussian noise (AWGN) channel was examined by estimating the average bit error rate (BER) for different carrier frequencies. The effect of the multipath fading, inband/outband interference, and adjacent channel power ratio (ACPR) has also been investigated during system assessment.

Modelling and simulation of wireless sensor system for health monitoring using HDL and Simulinkw mixed environment

The aim of this study is to model and design an efficient wireless system that is easy to integrate with other technologies or infrastructures at a low cost. The system would read analogue information recorded by a biomedical sensor in a transmitting unit attached to the patient. The recorded data are converted digitally using analogue-to-digital converter and sent to frequency-shift keying (FSK) transmitter through field programmable gate arrays (FPGAs). Verilog-HDL has been used to implement the required functions of the FPGA, such as bus interfacing, data buffering, compression and data framing. On the other hand, Simulink® software has been used to model and simulate FSK transmitter/receiver architecture suitable for short-range communications. Basically, a two-tone FSK signal is generated and passed through a noisy channel, which is then downconverted to baseband and passed to the frequency-modulating detector to restore the original transmitted bit stream. These illustrate how easily the mixed signal modelling can be well mapped into hardware description language (HDL) and mathematical programming techniques. The developed simulation models are used to explore the design change options. The behavioural HDL design has been interfaced to the Simulink model using system generator in a co-simulation environment, and the overall performance has been verified.