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An AI-Assisted IoT-Based Framework for Time Efficient Health Monitoring of COVID-19 Patients
Published in Bhawana Rudra, Anshul Verma, Shekhar Verma, Bhanu Shrestha, Futuristic Research Trends and Applications of Internet of Things, 2022
Punitkumar Bhavsar, Vinal Patel
Analog signals are converted to digital ones using A/D converters. A series of numeric numbers makes up a digital signal. These values can be readily stored and processed by modern computers. Sampling and quantization are the two basic stages in A/D conversion. To convert continuous time to discrete time, the sampling method is utilized. It entails determining the value of a signal at regular intervals. Every measurement is now referred to as a sample. If x(t) is an analog signal, it is sampled every T seconds, and x(kT) represents the amplitude value, with k (k = 0,1,2,3, … n) being the data sequence’s sample number and T being the sampling interval. The reciprocal of the sampling time (1/T) is the sampling frequency fs. To avoid distortions, the sampling frequency must be set higher than the maximum frequency of the source signal. The sample rate should be equal to or more than twice the highest frequency of the original signal, according to Nyquist’s theorem. If the maximum frequency in the signal is Fmax then minimum sampling rate is given by Fs = 2Fmax.
LIGHT SOURCES AND MODULATORS
Published in Glenn R. Elion, Herbert A. Elion, Fiber Optics in Communications Systems, 2020
Glenn R. Elion, Herbert A. Elion
Optic Modulator CharacteristicsMax.BeamBandwidthInsert.LossTypeMaterialA (nm)Dia.(mm)At 650 nmAt 650 nmEOLiNbOj.LiTaOj600-350015150 MHz5%KDP , ADP220-16504550 MHz10%AOdense glass400-22001010 MHz25%PbMo04400-22001050 MHz30%E0 = electro-optic modulatorAO = acousto-optic modulator Analog transmission sources can be digitized for use in optical systems usually by pulse code modulation (PCM) techniques. Digital transmission is preferred over analog for several reasons at the present stage of development of optical communications. First, signal regeneration at each repeater can be accomplished with a minimal amount of generated noise. Second, analog signals are more susceptible to noise and signal distortion. Third, the frequency division multiplex equipment used for analog systems is more expensive than the time division multiplex equipment used for digital transmission. The use of PCM with light source intensity modulation is relatively insensitive to noise since only the absence or presence of pulse energy is detected. This also permits clean pulse generation for reshaping and amplifying signals in the transmission line.
Data Conversion Process
Published in Michael Olorunfunmi Kolawole, Electronics, 2020
There is a strong motivation behind exploring a novel frontier of data processing that could benefit from cutting-edge miniature and power-efficient nanostructured silicon photonic devices. Recent example is photonic accelerator (PAXEL)—a processor that can process time-serial data either in an analog or digital fashion on a real-time basis [1]. Data processing is a way of converting data into a machine-readable form using a predefined sequence of operations. Communications signals can be analog or digital, and information can be transmitted using analog or digital signals. Analog signals are continuously changing in time (or frequency), while digital signals are discrete in time and amplitude. Interchangeability of information transfer allows the development of conversion processes without loss of detail. The challenge is to achieve a high sampling rate and high conversion accuracy in the presence of component mismatch, nonlinearity errors, and noise. Although the electronic circuits required to do this conversion processing can be quite complex, the basic idea is fairly simple. The basic concepts of data conversion and their inherent errors, as well as the choice of the converter types that strongly influence the architecture of the overall system, which are fundamental to the continuing revolution in information technology and communication systems, are explained in this chapter.
Acoustic Analysis of the Effects of Vapor-Liquid Interfacial Morphology on Pool-Boiling Heat Transfer
Published in Nuclear Technology, 2022
Mustafa H. Almadih, T. Almudhhi, S. Ebrahim, A. Howell, G. R. Garrett, S. M. Bajorek, F. B. Cheung
The sound wave signals that were produced from the boiling surface of the heated rod during quenching were analog signals. Signals produced or generated from natural sources, such as speech, artificial sources, and heat sources, are considered to be analog signals.14 Any continuous signal whose time-varying function is a reflection of another time-varying quantity is called an analog signal. In this study, the signals produced from the superheated rod during the quenching process are the input signals called analog signals. The hydrophone is built to record vibrating wave sounds underwater. The main goal is to record the generated sounds from the superheated rod and to convert all the analog signals into digital signals and then store them in the computer for analysis by using a data acquisition system connected to the computer through LabVIEW engineering system software for measurement (Fig. 9).
Quantitative Analysis of Aeroengine Turbine Disk Surface Crack under Natural Magnetic Field
Published in Research in Nondestructive Evaluation, 2022
Ping Fu, Bo Hu, Weitao Luo, Shaofei Wang, Xiwang Lan
The weak magnetic detection instrument includes hardware and software. The main modules of the hardware part include industrial control computer, a hard disk, a touch screen, a trackball, a lithium battery, and other components. As the magnetic sensor scans the test block at a constant speed, the instrument converts the detection signal into an analog signal, then transmits it to the integrated circuit board. Analog signals are converted into digital signals through an A/D converter. The digital signal is transmitted to the upper computer at the transmission speed of 10 Mbps through Ethernet UDP transmission protocol. Finally, the detection signal is displayed by operation software by an industrial control computer. The software part takes VisualStudio.net as the development platform and is written in c# language. The flux gate sensor is used as the magnetic sensor. The resolution, detection range, and sampling frequency of the sensor are 1nT, ±250000nT, and 12.5 Hz, respectively.
A full input range, 1–1.8 V voltage supply scalable analog voltage comparator in 180nm CMOS
Published in International Journal of Electronics, 2021
Ashima Gupta, Anil Singh, Alpana Agarwal
With the shrinking in MOS device size and rapid growth of technology, there is a demand for portable, compact, battery-operated, and lightweight devices that consume less area and power. Moreover, with the scaling down of the technology, for a substantial number of Complementary Metal Oxide Semiconductor (CMOS) circuits, power dissipation has become a critical design metrics. To process the real-world analog signals, they are first transformed into the digital domain through analog-to-digital converters (ADCs) because of the various advantages of being in the digital domain. The comparator is one of the essential building blocks of mixed-signal system designs, particularly in ADCs (Razavi, 2004). With the latest trends in the market to make things portable, lightweight with longer battery life, digital integrated circuit (IC) design has become a favourable choice than Analog IC designs (Wicht et al., 2004). Digital design methodology allows scalability, higher circuit density, and auto-placement and routing capability of CAD tools whereas analog designs are complex, take more time-to-market which makes them costly to achieve the same performance parameters (Wicht, 2011). Hence, there is a need to reconstruct the analog designs with a digital approach.