NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
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e greater than kR/n, as long as the amplifier response is linear, where R is the oversampling ratio, w is the angular stop b<strong>and</strong><br />
frequency <strong>and</strong> k is a parameter depending on structures <strong>and</strong> integrator circuit configuration, if a switched capacitor integrator<br />
is employed in a noise shaping technology. A second order delta modulation coder does not seem to be applicable to a precision<br />
converter, but to a high speed converter instead.<br />
Author<br />
Numerical Analysis; Operational Amplifiers; Amplifiers<br />
20060002111 Toledo Univ., OH, USA<br />
VLSI System Design Using a Macintosh Personal Computer<br />
Thorbjornsen, Arthur R.; Chin, Foh Hew; 1987 IEEE International Symposium on Circuits <strong>and</strong> Systems, Volume 2; 1987,<br />
pp. 530-531; In English; See also 20060002103; Copyright; Avail.: Other Sources<br />
This paper describes how a Macintoch Plus personal computer can be made to serve as a workstation for VLSI circuit<br />
design. The MacDraw graphics program is used to draw a circuit layout. A ‘C’ language proqram has been written that converts<br />
a MacDraw file into a CIF code description of the circuit layout.<br />
Author<br />
Macintosh Personal Computers; Systems Engineering; Very Large Scale Integration<br />
20060002112 Karlsruhe Univ., Germany<br />
A New Relative Placement Procedure Based on MSST <strong>and</strong> Linear Programming<br />
Weis, Bernd X.; Mlynski, Dieter A.; 1987 IEEE International Symposium on Circuits <strong>and</strong> Systems, Volume 2; 1987,<br />
pp. 564-567; In English; See also 20060002103; Copyright; Avail.: Other Sources<br />
The problem of placing cells on a carrier, i.e. a PCB or a chip, is usually divided into two steps. The first step is the<br />
computation of relative positions of cells, while the second prepares the placement such that the cells do not over-lap, <strong>and</strong><br />
sufficient area is provided for routing. For the first part the most commonly used algorithms are MIN-CUT <strong>and</strong> FORCE<br />
procedures. Here we introduce a formulation of the relative placement problem as a linear program, which minimizes the sum<br />
of weighted minimal spanning Steiner trees modelling the nets of the circuit. Gate arrays are used as examples.<br />
Author<br />
Algorithms; Linear Programming; Trees (Mathematics)<br />
20060002113 Korea Advanced Inst. of Science <strong>and</strong> Technology, Chongryang, Korea, Republic of<br />
Timing Simulator by Waveform Relaxation Considering the Feedback Effect<br />
Jun, Young-Hyun; Lee, Chang-Woo; Lee, Ki-Jun; Park, Song-Bai; 1987 IEEE International Symposium on Circuits <strong>and</strong><br />
Systems, Volume 2; 1987, pp. 608-611; In English; See also 20060002103; Copyright; Avail.: Other Sources<br />
Timing simulators are widely used nowadays for analyzing large scale MOS digital circuits. However, they have several<br />
limitations such as nonconvergence <strong>and</strong>/or inaccuracy for circuits containing tightly coupled feedback elements or loops. This<br />
paper describes a new timing simulator which aims at solving these problems. The algorithm employed is based on the<br />
waveform relaxation method, <strong>and</strong> exploits the signal flow along the feedback loops. Each of the feedback loops is treated as<br />
one circuit block <strong>and</strong> then local iterations are performed to enhance the timing simulation. An approach to partitioning<br />
bidirectional subcircuits is also presented.<br />
Author<br />
Digital Electronics; Feedback; Simulators; Waveforms<br />
20060002114 California Inst. of Tech., Pasadena, CA, USA<br />
New Normal-Forms for IIR Filter Realizations, Based on Circulants <strong>and</strong> Skew-Circulants<br />
Liu, Vincent C.; Vaidyanathan, P. P.; 1987 IEEE International Symposium on Circuits <strong>and</strong> Systems, Volume 2; 1987,<br />
pp. 637-640; In English; See also 20060002103<br />
Contract(s)/Grant(s): NSF DCI-85-52579; Copyright; Avail.: Other Sources<br />
Normal-form IIR filters are known to be free from limit cycles, <strong>and</strong> the eigenvalues of the state transition matrix have<br />
low sensitivity. In this paper two new normal form realizations are presented which utilize circulant <strong>and</strong> skew-circulant<br />
matrices as their state transition matrices. The A-matrix has only N (rather than N(sup 2)) distinct elements, <strong>and</strong> is amenable<br />
to efficient memory-oriented implementation. Scaled circulant realizations are developed based on iterative methods.<br />
Author<br />
Cycles; Matrices (Mathematics); Eigenvalues; IIR Filters<br />
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