Design and Simulation of Two Stage Wideband CMOS Amplifier in 90 NM Technology

Design and simulation of 7 GHz CMOS wideband amplifier(CMOSWA) using a modified cascode circuit realized in  90-nm CMOS technology is presented here. The proposed system consists of two stages, namely a modified folded cascode and an inductively degenerated common source amplifier. The circuit is experimented with and without a feedback network. This work discusses the performance variation as a function of reactive components, and the initial stage results in 22 dB gain,2.6 GHz bandwidth, and 40GHz unity gain-bandwidth. The circuit without the feedback network exhibits 30.7dB gain,4.8GHz bandwidth(BW), and 10GHz unity-gain bandwidth(UGB). The reactive feedback network's inclusion helped to achieve 38.7 dB gain, 6.95GHz BW, 30GHz UGB, and 55o phase margin. The circuit consumes 1.4mW power from a 1.8V power supply. Simulation results of the proposed circuit are comparable and better than the reported wideband designs in the literature. Realization of our proposed circuit would add value to the area of wideband amplifier design

Determination of Location and Orientation of 3-Axis Accelerometer for Detecting Gait phase, Duration and Speed of Human Motion for Development of Prosthetic Knee

The paper discusses results of experiments carried out at healthy individuals with an aim to establish an in-house developed sensor mechanism using ADXL 330 accelerometer. The sensor was developed in view to measure gait phases (heel strike & toe off), gait duration and gait speed. These findings were useful in understanding the range of normal gait though accelerometer and further used for control of indigenously developed artificial electronic knee

EMG Signal Analysis for Identifying Walking Patterns of Normal Healthy Individuals

Surface electromyography is the technique for measuring levels of muscle activity. When a muscle contracts, electrical activity generated as action potentials propagate along the muscle fibers. There are two types of Surface EMG (SEMG)-Static scanning SEMG and Dynamic SEMG. In Dynamic SEMG, electrodes are attached to the skin and muscle activity is measured and graphed as the patient moves through various ranges of motion. The authors in this paper discuss the use of EMG for analyzing different phases of walk by acquiring the surface EMG from Gastrocnemius and Soleus muscles of the leg .with the subjects walking at two self selected pace- fast and slow. These surface EMG signals picked up during the muscle activity are interfaced with a PC system via Biometrics EMG acquisition system. The acquired signals were processed and analyzed using filtering techniques. The results showed a marked variation in the RMS amplitude levels and median frequency of EMG as the subject’s walking pace changed

Knowledge base generation and its implementation for control of above knee prosthetic device based on SEMG and knee flexion angle

Advanced intelligent knee prosthesis for trans-femoral amputees requires a versatile control strategy and associated control algorithm. Control strategy was evolved by mapping surface EMG (SEMG) from four muscles of healthy lower limb of a unilateral trans-femoral amputee and knee flexion angles (KFA) during various phases of a gait cycle. The SEMG and KFA are calibrated to three walking speeds modes i.e., slow, normal and fast. Sensor mechanisms feeds real-time data to controller to generate an appropriate control output signal based on available knowledgebase which calculates the patient's gait parameters i.e., KFA and SEMG from associated muscles during the corresponding phase of walk. Important aspect of control strategy is the development of knowledgebase proves that the SEMG signal generates recognisable pattern for change in walking speed when signals were analysed in time and frequency domain. These patterns were quantified and utilised for controlling electro-pneumatic knee joint

Active Marker based Kinematic and Spatio-Temporal Gait Measurement System using LabVIEW

This study presents an automated, easy to use, cost-effective, patient-friendly, active marker based gait measurement (GM) system for 2-D tracking and extraction of spatio-temporal parameters of human gait. Active markers, consisting of visible light-emitting diodes (LEDs), were positioned at anatomical landmarks to measure coordinated kinematics of human joints.Acquired image data were processed and analyzed using LabVIEW vision for determination of spatio-temporal parameters

Lower Body Gait Analysis using Biometrics Twin Axis Goniometers

The joint angles of the lower limb are important parameters in evaluating the ability and stability of the walk. The individuals differ in their walking styles because of differences in flexion/ extension angles of hip, knee and ankle joints. The simplest method of measuring joint angles is placing goniometers along these joints. Although this method is prone to error and have very little scientific information contained other than joint angle values, different phases and subphases of gait can be categorized in terms of these angles. The joint angle measured from the normal functioning lower limb of the patient can be used as part of a feedback mechanism that guides the prosthetic mechanism employed on the affected/amputated limb to produce very similar angular movement to execute stable walking pattern. Authors measure human joint movement angles using Biometrics Twin Axis Goniometers in order to analyze the joint angle patterns and mapping them for normal gait. These angles information can be used as a feedback in controlling the flexion/extension of prosthetic