The Impact of Using Digital Filter and Analog Filter on Surface Electromyography Signal

Many accident cases result in humans having to going a surgery to save them, then performing muscle therapy to help the patient’s recovery after going through the post-surgery. The purpose of this therapy is the patient’s body to its normal state. Exoskeleton is an additonal clothing-like tool that aims to both protect and increase the wearer's abilities. Meanwhile electromyography (EMG) is a technique to evaluate and record the electrical activity produced by skeletal muscles. The purpose of this study was to analyze the differences in using of analog and digital filters on EMG, as well as the effect on the exoskeleton simulation. The method used in the main design consists of the myoware module, notch circuit, low pass filter, arduino uno, DAC module, teraterm software, and matlab. The intercepted signal was taken from the biceps using a disposable electrode (AG/AGCL.). The EMG signal tapped by the myoware module then is continued to another circuit, then was recorded on the Teraterm software, and analyzed in MATLAB. The voltage value on the analog filter is 1.541 Volt during relaxation and 2.086 Volt during contraction, while the digital filter that has passed through the DAC has a value of 41.8 mVolt during relaxation and 269.1 mVolt during contraction. The results of this study obtained that digital and analog filter values ​​have an average difference of 5 to 30. The conclusion of this research is that the tool can detect changes in the use of analog and digital filters. Therefore, in the future research, development can be made to compare other types of digital filters along with replacement to wireless systems. The benefit or purpose of this research is as a simulation of exoskeleton skeletal motion and to see the difference between the use of digital and analog filters.

Control-Bounded Analog-to-Digital Conversion

A control-bounded analog-to-digital converter consists of a linear analog system that is subject to digital control, and a digital filter that estimates the analog input signal from the digital control signals. Such converters have many commonalities with delta–sigma converters, but they can use more general analog filters. The paper describes the operating principle, gives a transfer function analysis, and describes the digital filtering. In addition, the paper discusses two examples of such architectures. The first example is a cascade structure reminiscent of, but simpler than, a high-order MASH converter. The second example combines two attractive properties that have so far been considered incompatible. Its nominal conversion noise (assuming ideal components) essentially equals that of the first example. However, its analog filter is a fully connected network to which the input signal is fed in parallel, which potentially makes it more robust against nonidealities.

Introduction to this special section: Surface-wave applications

The use of surface waves can be found at all levels of seismology, from the near surface to exploration to earthquakes. Once the scourge of reflection processing, the need to remove this coherent noise source led to a variety of in-field techniques to minimize its impact, including the application of geophone arrays, low-cut analog filters, and high-frequency geophones, not to mention the multitude of processing schemes devised to reduce surface-wave amplitudes after data collection. Although commonly labeled as noise, surface waves have proven to be versatile and resilient over the years, lending themselves to engineering applications in the shallow subsurface and developing velocity models to improve complex imaging in the oil and gas sector. This special section includes six papers that are equally representative, running the gamut from the first few meters of the surface to hundreds of meters deep. It includes examples of active and passive acquisition, modeling and field data, as well as geophones and fiber-optic sensors.

Method for Assessment of Operation of Analog Filters Installed in the Measuring Lines for Electrical Quantities of a Mining Machine’s Converter Power Supply System

A method for assessing the operation of analog filters installed in the measuring paths of current and voltage converters in the power supply system of a mining machine motor, using the example of the driving unit of a roadheader’s cutterhead, is presented. The suggested method is based on the identification of the fundamental harmonic of signals from the current and voltage sensors observed at the input and output of the tested filters, respectively. The identified parameters of the fundamental harmonic of signals before and after the filter allow the determination of points of the filter frequency’s characteristics and their comparison with the reference values. In the suggested method of assessing the operation of analog filters, the new approach consists of checking the frequency characteristics on the basis of identification of the basic harmonics of the signal at the input and output of the tested filter (installed in the measuring line of the electrical quantity) using data acquired during the frequency start-up of the mining machine driving motor under normal operational conditions. Results are presented of the filter performance assessment, using the suggested method, after three years of its operation in the measuring system. For this purpose, empirical data recorded during the operation of a roadheader on a test stand are used. The results are compared with the theoretical frequency characteristics of the tested filters.

Optimized Analog Multi-Band Carrierless Amplitude and Phase Modulation for Visible Light Communication-Based Internet of Things Systems

This paper presents a multi-user Visible Light Communication (VLC)-based Internet of Things (IoT) system using multi band-Carrierless Amplitude and Phase (m-CAP) modulation for IoT applications. The proposed system uses a digital m-CAP modulator embedded in a ceiling LED light fixture and analog receivers, aiming at low-cost, low-power, and small-sized IoT devices. The performance was evaluated in terms of the filtering stage design and the usage of guard bands. Different pairs of emitter and receiver filters were considered. While Bessel and Butterworth analog filters were tested in the analog receiver, the digital m-CAP modulator pulse shaping filter considered raised cosine filters, as well as digital matched filters for the analog Bessel and Butterworth filters. Regarding the guard bands, two approaches were considered: either by using the raised cosine roll-off factor (bandwidth compression) or by suppressing the even bands. The Bit Error Rate (BER) performance was obtained by simulation. The usage of the Bessel filter in the receiver, along with a digital matched filter, proved to be the best solution, achieving a BER lower than 10−3 for an Eb/No of 6 dB, using a third-order filter. Furthermore, guard bands should be used in order to mitigate inter-band interference in order to have improved performance when multiple users intend to simultaneously communicate.

Analog Filters Design for Improving Precision in Proton Sound Detectors

This paper analyzes how to improve the precision of ionoacoustic proton range verification by optimizing the analog signal processing stages with particular emphasis on analog filters. The ionoacoustic technique allows one to spatially detect the proton beam penetration depth/range in a water absorber, with interesting possible applications in real-time beam monitoring during hadron therapy treatments. The state of the art uses nonoptimized detectors that have low signal quality and thus require a higher total dose, which is not compatible with clinical applications. For these reasons, a comprehensive analysis of acoustic signal bandwidth, signal-to-noise-ratio and noise power/bandwidth will be presented. The correlation between these signal-quality parameters with maximum achievable proton range measurement precision will be discussed. In particular, the use of an optimized analog filter allows one to decrease the dose required to achieve a given precision by as much as 98.4% compared to a nonoptimized filter approach.

A Meticulous Method for the Measurement of Partial Discharges in Gas Insulated Switchgears

This Paper presents the application of modern & meticulous procedure for the measuring Partial Discharge on the GIS (Gas Insulated Switchgear). The conventional method was by the usage of analog filters and the comparison between the induced and circulating currents, here we made use of the ultra-high frequency sensors which detects the ultra-high frequency signals that were produced during the abnormal condition. The UHF sensors are placed on the Gas Insulated Switchgears at the suitable designed location. The detected signal is digitized and transmitted to the control panel via the high speed fiber optic cables. It is processed and the cause for the partial discharge is known. At site it is done along with the high voltage measurement of the GIS. The final measured value is measured in Pico coulombs.