Logic Rating of Electromechanical Relays
Electromechanical relays were the first logic element used in a computer. Today, small compact reed relays are again being extensively used as logic elements. A logic factor, FL, measures the improvement that a logic device can affect if interposed between a logic source and logic detector. A logic figure of merit, TFM, determined when FL = 1.0 can be used for comparison of the logic performance of logic devices. TFM is developed for an arbitrary electromechanical relay. For a miniature reed relay packaged for printed circuit boards, TFM = 1.7 milliseconds. For comparison, solid-state devices have TFM ¿ 1 nanoseconds and COSMOS (complementary symmetry metal oxide semiconductor) devices have TFM ¿ 20 nanoseconds.
On measures of logic performance: logic quantum, factor, and figure of merit
A basic logic operation is considered of transferring a logic decision from one point to another point. A certain energy level, WL, corresponding to decision threshold and a time delay, TL, are encountered in the transfer process. The product, WLTL, is a logic quantum, HL. If the logic transfer takes place through an intermediate device, a logic factor, FL, can be introduced to describe the reduction in logic quanta that the device can produce under optimum conditions. Optimization is carried out, as for instance with ideal transformers, to "match" the logic source to the device and the device to the logic detector. The condition FL = 1 marks a boundary between a useful and a uselessd evice, and a logicf igure of merit, TPH,in units of time corresponds to the fastest source-detector combination such that FL = 1. Logic performance is considered in some detail for a particular linear model of a device. Nonlinear devices and relay devices are considered in less detail, although some numerical calculations are given for a current-switch, two-transistor computer device. The logic figure of merit represents a unique measure of high-speed logic performance and is therefore valuable in comparing devices including associated circuitry on a common basis.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).