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Analog and Digital VLSI Design
Published in Bogdan M. Wilamowski, J. David Irwin, Fundamentals of Industrial Electronics, 2018
Data converters form the interface boundary between the analog and digital domains. An analog-to-digital converter (ADC) samples an analog signal at a given clock rate, quantizes it, and represents it in its equivalent digital code. On the other hand, a digital-to-analog converter (DAC) converts a digital input code into its analog representation. ADCs can be categorized into two broad categories, namely Nyquist rate and oversampling data converters. Nyquist-rate ADCs operate at a sampling frequency, set by Nyquist’s sampling theorem, which is double the bandwidth of the input analog signal. A wide variety of Nyquist-rate ADC architectures are available spanning the spectrum of speed and resolution: flash, pipelined, subranging, folding, integrating, and successive approximation.
Implementation of Digital Control Using Digital Signal Processors
Published in Ali Emadi, Alireza Khaligh, Zhong Nie, Young Joo Lee, and Digital Control, 2017
Ali Emadi, Alireza Khaligh, Zhong Nie, Young Joo Lee
A digital-to-analog converter (DAC) is used to convert the digital operation results into analog signals, which is a final process of digital signal processing. In addition, DAC is useful in monitoring the internal calculation results in almost real time. The software developer is able to trace the calculation results from control routines by watching the oscilloscope. In order to store user parameters in the control system, EEPROMs are frequently used. When internal EEPROM is not available, the designer adds external EEPROMs to DSP chips or μ-controllers. Introducing DAC and EEPROM with serial interfaces reduces the number of wires in connecting DSP chips with external devices. Many DSP chip or μ-controller programmers use the JTAG port to download and emulate the user program on the basis of the boundary scan technology. For a software developer’s convenience, many DSP chip and μ-controller manufacturers provide a JTAG port on their products as well as a JTAG downloader and emulator. Figure 16.18 shows the schematic for serial interface of DAC, EEPROM, and JTAG.
Introduction
Published in Anastasia Veloni, Nikolaos I. Miridakis, Erysso Boukouvala, Digital and Statistical Signal Processing, 2018
Anastasia Veloni, Nikolaos I. Miridakis, Erysso Boukouvala
The digital signal processor may be a computer or a microprocessor, which is programmed to perform the desired operations on the input signal. In applications where the digital output from the digital signal processor is to be given to the user in analog form, as, for example, in speech communication, another circuit has to be mediated between the digital and the analog region. A circuit that receives a digital input and converts it into analog is a digital to analog converter (DAC). A key feature of DACs is the accuracy in which the converter can change the output. This accuracy is a function of the number of the n bits (2n levels of quantization) that the digital circuit of the converter can operate at.
Deep Learning Techniques for OFDM Systems
Published in IETE Journal of Research, 2021
M. Meenalakshmi, Saurabh Chaturvedi, Vivek K. Dwivedi
The CP replicates a part of data from the end to the beginning of each OFDM symbol to create the guard period, which overcomes the inter symbol interference (ISI) caused by delay dispersion. Subsequently, the signal is converted from digital to analog form using a digital-to-analog converter (DAC). Then the analog signal is transmitted over-the-air by a radio frequency (RF) front end at the transmitter. The transmitted RF signal is propagated over the wireless channel and received by the RF front end at the receiver. The received analog signal is passed through an analog-to-digital converter (ADC) and then the CP is removed. In the next step, the serial data are converted into parallel form to perform the FFT operation. The FFT operation converts the time-domain data into the frequency domain and then the pilot symbols are extracted for channel estimation. Lastly, the P/S converter converts the parallel data into serial form and then the data are demodulated to recover the original input data.
Real-Time Implementation of Iterative Learning Control for an Electro-Hydraulic Servo System
Published in IETE Journal of Research, 2023
C. Naveen, B. Meenakshipriya, A. Tony Thomas, S. Sathiyavathi, S. Sathishbabu
The spool-valve displacement is controlled by the input current given to the torque motor of the servo valve. The piston's spool position and load circumstances are used to determine the rate and direction of flow to each cylinder chamber. The data acquisition card (DAQ) is used to regulate the press cylinder automatically. The DAQ communicates with the programming device and EHSS. It comprises a digital-to-analogue converter (DAC) and an analogue-to-digital converter (ADC). The ADC receives the signal from the LVDT and converts the analogue piston displacement signal into a digital signal. The DAC receives the signal from the controller and converts the signal into an appropriate pulse width modulated analogue signal and is sent to the servo valve through the driver.
Analysis of real-time jitter in cyber-physical applications using frequency domain perturbation
Published in International Journal of General Systems, 2023
Ricardo Cayssials, Edgardo Ferro
A continuous-time domain input signal I(t) is converted from analog to digital by an analog-to-digital converter (ADC) at sampling times, producing the discrete-time signal I(k) (Figure 2 shows how I(k) varies in time). The real-time task processes the input data I(k) and produces the output data O(k) at the sampling rate. The digital-to-analog converter (DAC) is updated with the output data, O(k), in order to produce the continuous-time signal O(t).