iran is a rather wide country, and, as a rule, the chrage per one call in s. t .d . (subscriber trunk dialing ) is required more compared with a local call , so, just after the opening of the std service widely in national telephone network, unconcerned use of the s. t. d. service has been caused on an incon- ceivable increase in telephone charge of th subscriber. this is a common problem for a...

the types of transmission systems which today are available for long distance transmission of large numbers of telephone circuits are those for coaxial cables and radio links. the number of circuits is increased in both cases in step with development in technique. radio links have for several years been able to transmit 600 telephone circuits per system. and are now being designed for 960 circu...

Today, the use of CMOS technology for the manufacture of electronic ICs has faced many limitations. Many alternatives to CMOS technology are offered and made every day. Quantum-dot cellular automata (QCA) is one of the most widely used. QCA gates and circuits have many advantages including small size, low power consumption and high speed. On the other hand, using special digital gates called re...

In this work, we present two memristor based chaotic circuits. These circuits are obtained by replacing the nonlinear resistor in the four element Chua’s circuit with a memristor. Hence, these chaotic circuits use only the four basic circuit elements. Moreover, one of these circuits has only one negative element in addition to the nonlinearity. The four element Chua’s circuit requires two negat...

Reversible logic is one of the new paradigms for power optimization that can be used instead of the current circuits. Moreover, the fault-tolerance capability in the form of error detection or error correction is a vital aspect for current processing systems. In this paper, as the multiplication is an important operation in computing systems, some novel reversible multiplier designs are propose...