52 APLAC, a general purpose circuit simulation and design tool

(from Sakari Aaltonen <sakari@picea.hut.fi>)

               APLAC 6.2
General information

APLAC, a program for circuit simulation and analysis, is a joint development of the Circuit Theory Lab of Helsinki University of Technology and Nokia Corporation's Research Center. The main analysis modes are DC, AC, noise, transient, oscillator, and (multitone harmonic) steady state. APLAC can also be used for measurements with IEEE-488 apparatus. APLAC's transient analysis uses convolution for correct treatment of components with frequency-dependent characteristics. Monte Carlo analysis is available in all basic analysis modes, as is sensitivity analysis in DC and AC modes. N-port Z, Y, and S parameters, as well as two-port H parameters, can be used in AC analysis. APLAC also includes a versatile collection of system level blocks for the simulation and design of analog and digital communication systems.

Component models

Too many to be listed here. In addition to familiar Spice models, a great number of microwave components (microstrip/stripline) are included. System models include formula-based and discrete-time models useful in RF design. The model parameters of the components may have any functional dependency on frequency, time, temperature, or any other parameter. Users can create new components by defining their - possibly nonlinear - static and dynamic characteristics in APLAC's interpreter-type language. Spice-syntax models can be imported.


APLAC reads its input - the nodes, branches, and model parameters of the components - from a text file. Model libraries can be created and included. Expressions are written in a program-like manner; user functions may be defined. Conditional and looping control structures are supported.


The output results from one or several sweeps of any user-defined function of the circuit parameters, time, frequency, or temperature. The results may be printed or plotted in rectangular or polar coordinates, or on the Smith chart. Graphics output can be directed to an HPGL- or CSDF-type file, or to a graphics file for later viewing.


APLAC includes several optimization methods: gradient, conjugate gradient, minmax, random, simulated annealing, tuning (manual optimization) and gravity center (design centering). Any parameter in a design problem can be used as a variable and any user-defined function may act as an objective.

Machine environment

Unix: X11; PC: MS-Windows (math coprocessor required).

Contact information
Martti Valtonen 			Heikki Rekonen
Helsinki University of Technology 	Nokia Research Center
Circuit Theory Laboratory               Hardware Design Technology
Otakaari 5A, SF-02150 Espoo, FINLAND    P.O.Box 156, SF-02101 Espoo,
Fax:  358-0-460224 			Tel:  358-0-43761
e-mail:martti@aplac.hut.fi 		Fax:  358-0-455 2557
A WWW server is available at <URL:
http://picea.hut.fi/aplac/main.html>, and an experimental hypertext tutorial is at <URL:http://picea.hut.fi/aplac/tutorial/main.html>

This document was translated by ms2html v1.7 on 16.01.97. OMN

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