Suhaidi Shafie
Universiti Putra Malaysia (UPM)

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Optimized low voltage low power dynamic comparator robust to process, voltage and temperature variation Julie Roslita Rusli; Suhaidi Shafie; Roslina Mohd Sidek; Hasmayadi Abdul Majid; W. Z. Wan Hassan; M. A. Mustafa
Indonesian Journal of Electrical Engineering and Computer Science Vol 17, No 2: February 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v17.i2.pp783-792

Abstract

Power consumption and speed are the main criteria in designing comparator for analog-to-digital converter (ADC).  This paper presents an optimized low voltage low power dynamic comparator which is robust to process, voltage and temperature (PVT) variations with adequate speed.  The comparator circuit was designed using 0.18µm CMOS technology with low voltage supply of 0.8V.  The method used to verify the robustness of the comparator circuit across 45 PVT is presented.  The circuit is simulated with 10% voltage supply variation, five process corners and temperature variation from 0°C to 100°C. The simulation result show that the proposed comparator circuit achieved significant reduction of power consumption and delay during worst case condition compared to dynamic comparator proposed from previous researchers.
Differential input range driver for SAR ADC measurement setup Siti Idzura Yusuf; Suhaidi Shafie; Hasmayadi Abdul Majid; Izhal Abdul Halin
Indonesian Journal of Electrical Engineering and Computer Science Vol 17, No 2: February 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v17.i2.pp750-758

Abstract

Differential successive approximation register (SAR) of analog to digital converter (ADC) requires two balancing input signals that have same amplitude with 180⁰ out of phase. Otherwise, it performs inaccurately and degrades the performance during ADC testing procedure. Therefore, an implementation of AD8139 chip single to differential amplifier was chosen as an ADC driver to generate sufficient differential output for the ADC. The chip was placed on a printed circuit board (PCB) to test the functionality as well as the performance of static and dynamic SAR ADC. The result shows that the single-ended input transform into differential voltage outputs. The amplitudes for the amplifier remain equal and is 180° out of phase for DC and AC voltage input signal. Besides, the fabricated 0.18µm CMOS technology of differential 10-bit SAR ADC is capable of digitising full code digital output and perform 9.5-bit effective number of bit (ENOB) from analog input driving by the ADC driver.
Amplitude independent versus amplitude dependent muscle activity detection algorithms: a comparative study Husamuldeen K. Hameed; W. Z. Wan Hasan; Suhaidi Shafie; Siti Anom Ahmad; Haslina Jaafar
Indonesian Journal of Electrical Engineering and Computer Science Vol 17, No 2: February 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v17.i2.pp583-593

Abstract

The amplitude dependent muscle activity detection algorithms of the surface electromyography (sEMG) signals are very sensitive to the changes in the background noise levels and the performance of these amplitude-based methods is highly deteriorated when the Signal to Noise ratio (SNR) of the sEMG signal is low. sEMG signals of deep and small muscles as well as sEMG signals recorded from patients that have neuromuscular diseases may not meet this SNR requirement which motivates the need for amplitude independent algorithms that can detect weak muscle activities. Moreover, the sEMG signal amplitude is not constant during the recording time due to the variation in the characteristics of the electrode-skin interface and due to the changes in the ground reference level. Therefore, the performance of the muscle activity detection algorithms should not be affected by the involuntary amplitude variations of the sEMG signal in order to achieve reliable control of robotic devices intended for disabled people.To accentuate the importance of the amplitude independent muscle activity detection methods over the amplitude dependent detection methods, a comparative study has been conducted in this paper between the performance of an amplitude independent muscle activity detection algorithm (FLA-MSE algorithm) and three amplitude dependent algorithms with respect to the detection capability of weak muscle activities and with respect to the immunity against false alarms. The results have showed that the performance of the amplitude independent algorithm outperformed the performance of the amplitude dependent algorithms for detecting weak muscle activities and for robustness against false alarms.