Basic EMC (electromagnetic interference) technology advancement for c3 systems. Volume 3A: Probabilistic analysis of combinational circuits with random delays
Abstract
Random propagation delays are encountered in digital integrated circuits due to fluctuations in the fabrication process. These delays can be further increased due to the presence of electromagnetic interference. System performance can be evaluated from the expected values of the output signals. Analytical methods for determining the output expected values of combinational circuits with random delays are developed in this dissertation. Given the input expectations, the network logic functions, and p.d.f.'s of the delays associated with the gates of the network, it is shown how to obtain the output expected values. Two types of delay elements are considered: (1) the pure delay elements, whose output is a delayed, but undistorted, replica of the input, and (2) the discriminating delay element, where input rise and fall transitions experience different delays. Two degrees of network complexity are dealt with: (1) treelike networks, in which there is only one path from every network input to any network, and (2) networks with reconvergent fanouts, where more than one path exists from some inputs to some outputs. To simplify analysis of very large circuits, an approximate model is proposed where the circuits are subdivided into large logic blocks. The analytical techniques previously derived for individual gates are then applicable. Various strategies for characterizing the delays of the large logic blocks are considered and examined by means of computer simulations.
 Publication:

Final Report
 Pub Date:
 August 1984
 Bibcode:
 1984scee.reptQ....E
 Keywords:

 Command And Control;
 Electromagnetic Interference;
 Gates (Circuits);
 Integrated Circuits;
 Logic Circuits;
 Computerized Simulation;
 Delay;
 Electromagnetic Compatibility;
 Input;
 Output;
 Probability Theory;
 Random Processes;
 Telecommunication;
 Communications and Radar