Symbol Circuil Realization

Use of current-mode CMOS circuits for implementation of multiple-valued logic (MVL) functions has been consid-ered in a number of recent papers. In this paper, we present an application of these circuits in realization of Galoisfield operations. We also give a new algorithm for determination of polynomial representations for arbitrary functions over a class of Galoisjelds implementable with presently available MVL circuits. 1.0 Current-Mode MVL Functions Recent experience shows that current-mode circuits are attractive for implementation of MVL functions, particu-larly when the radix is greater than 3. Most of the circuits and synthesis techniques in the literature have been intended for the 4-valued environment [Z], [41, [5]. Cur-rent-mode circuits offer several advantages, but they also have some disadvantages. Perhaps the most important of these are the ease of summation of signals and the diffi-culty in distribution of signals caused by the fanout being equal to one. In practice, it is useful to augment the cur-rent-mode circuits with some intermediate voltage-mode circuits, which often results in more effective designs. Figure 1 gives the basic blocks used in our design. All of these blocks have been used before [2], [4], [5]. Here, we will only summarize their characteristics. Currents are summed by means of a simple wired con-nection. Current sources are realized as an N-type or a P-type transistor with the gate connected to a reference volt-age. The amount (value) of current is proportional to the ratio of W/L. Signal distribution can be performed using current m'r-rors, which can be of either N-type or P-type. We will use both types. The current produced at the output is deter-mined by the input current and the ratio between output and input W/L values. In addition to signal distribution, the current mirror will be used for multiplication with a constant and for sign reversal