China
Africa
Explore chapters and articles related to this topic
Embedded Computing Systems and Hardware/Software Codesign
Published in Wai-Kai Chen, Computer Aided Design and Design Automation, 2018
Microprocessors are generally categorized by their word size, since word size is associated both with maximum program size and data resolution. Commercial microprocessors come in many sizes; the term microcontroller is used to denote a microprocessor which comes with some basic on-chip peripheral devices, such as serial input/output (I/O) ports. Four-bit microcontrollers are extremely simple but capable of some basic functions. Eight-bit microcontrollers are workhorse low-end microprocessors. Sixteen- and 32-bit microprocessors provide significantly more functionality. A 16/32-bit microprocessor may be in the same architectural family as the CPUs used in computer workstations, but microprocessors destined for embedded computing often do not provide memory management hardware. A digital signal processor (DSP) is a microprocessor tuned for signal processing applications. DSPs are often Harvard architectures, meaning that they provide separate data and program memories; Harvard architectures provide higher performance for DSP applications. DSPs may provide integer or floating-point arithmetic.
An Introduction to Control Systems
Published in Arthur G.O. Mutambara, Design and Analysis of Control Systems, 2017
Discrete data control systems differ from continuous-data systems in that the signals at one or more points of the system are in the form of either a pulse train or a digital code. Usually, discrete-data control systems are subdivided into sampled-data and digital control systems. Sampled-data control systems refer to a more general class of discrete-data systems in which the signals are in the form of pulse data. A digital control system refers to the use of a digital computer or controller in the system, so that the signals are digitally coded, such as in binary code. In general, a sampled-data system receives data or information only intermittently at specific instants of time. A sampled-data system can also be classified as an AC system since the signal of the system is pulse modulated.
Centrifuge data acquisition systems
Published in Gopal Madabhushi, Centrifuge Modelling for Civil Engineers, 2015
A key stage in the data acquisition process as outlined in Figure 9.1 is the analog to digital conversion. As explained earlier, instruments produce an analog signal which is continuous with time. A digital signal by definition is a set of discrete values at each of the time increments. The range of the A/D card is divided into a number of steps. Thus, a continuous signal appears as a series of step functions. This is illustrated in Figure 9.2, which shows a continuous sinusoidal signal of ±1 V. This signal is digitized at 10 discrete levels, each a step of 0.2 V, and fits the continuous sine wave. At each time instant only a discrete value is logged. Clearly, the more discrete levels there are, the more closely the digital signal will match the analog signal.
Optimization–based decoding algorithms for LDPC convolutional codes in communication systems
Published in IISE Transactions, 2019
Banu Kabakulak, Z. Caner Taşkın, Ali Emre Pusane
Digital communication systems transmit information from a sender to a receiver over a communication channel. Communication channels are unreliable environments, such as air, that many sender–receiver pairs share. Hence, during transmission some of the transmitted symbols can be lost or their values can change. In coding theory, information is encoded in order to overcome the occurence of such errors during the transmission. Let the information to be sent be represented by a k–bits long sequence . In order to test whether the information is sent correctly or not, parity bits are added by the encoder. This is done with a k × n generator matrix G through the operation (mod 2). As a result, an n–bits long codeword is obtained. Without loss of generality, we can assume that the first k bits of the codeword are information bits, and the remaining n – k bits are parity bits.