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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
systolic components. If the S/N and power gain of each individual component in the system is known, then Friis' formula can be used to predict the overall system noise factor: system NFd B = 10 log10 NR1 + (NR2 - 1) /PG1 + (NR3 - 1) / (PG1 × PG2 ) + (NR4 - 1) / [PG1 × PG2 × PG3 ] + · · · + (NRn - 1) / PG1 × PG2 . . . PG(n-1) where all values for S/N and power gain are in ratio (non-decibel) format, and the noise ratio, NR, of each stage is defined as NR = (S/Ninput )/(S/Noutput ). Also referred to as system noise figure. System Performance and Evaluation Cooperative (SPEC) a cooperative formed by four companies, Apollo, Hewlett-Packard, MIPS, and Sun Microsystems, to evaluate smaller computers. systematic code a code for which the information sequence itself is a part of the coded sequence. For block codes, it is common to assume that the information sequence is the first (or last) part of the codeword. system transfer function the result of sending a known test signal (often an impulse function or sine wave) through a system that defines what system with memory a system whose output at time t depends on the input at other times (and possibly including) that instant t. If the output of the system at time t depends only on the input to the system at time t the system is said to be memoryless. systems engineering an approach to the overall life cycle evolution of a product or system. Generally, the systems engineering process comprises a number of phases. There are three essential phases in any systems engineering life cycle: formulation of requirements and specifications, design and development of the system or product, and deployment of the system. Each of these three basic phases may be further expanded into a larger number. For example, deployment generally comprises operational test and evaluation, maintenance over an extended operational life of the system, and modification and retrofit (or replacement) to meet new and evolving user needs. systolic flow of data in a rhythmic fashion from a memory through many processors, returning to the memory just as blood flows from and to the heart. a system will do when presented with an input signal. Test signals often must be varied in frequency since system transfer functions are often frequency dependent (e.g., a stereo amplifier or speakers).
Series concatenation of 2D convolutional codes by means of input-state-output representations
Published in International Journal of Control, 2018
Joan-Josep Climent, Diego Napp, Raquel Pinto, Rita Simões
Note that the fact that two equivalent encoders differ by unimodular matrix multiplication also implies that the primeness properties of the encoders of a code are preserved, i.e. if admits a rFP (rZP) encoder then all its encoders are rFP (rZP). A 2D finite support convolutional code that admits rFP encoders is called non-catastrophic, and it is named basic if all its encoders are rZP. An encoder of the form up to a row permutation is called systematic. Not all 2D convolutional codes admit a systematic encoder. We call 2D systematic code to a 2D convolutional code that admits a systematic encoder. The class of 2D systematic codes is contained in the class of the 2D basic convolutional codes as the following lemma implies. The proof is straightforward and we omit it.