Airborne signal intelligence (SIGINT) systems must be capable of locating radio signal sources. Direction finding (DF) to support this capability is an important factor. There are some practical considerations to be taken when designing the array configuration of a DF system for airborne SIGINT systems. This paper summarizes the practical factors when designing the array configuration of the DF system for airborne SIGINT. In particular, it focuses on four areas: antenna consideration factors when installing the DF system for airborne SIGINT from a practical point of view, array configuration methods for airborne communications intelligence and electronic intelligence, and a numerical analysis to select the optimum antenna position for airborne SIGINT.

A parallel memory system for efficient parallel array access using perfect latin squares as skewing functions is discussed. Simple construction methods for building perfect latin squares are presented. The resulting skewing scheme provides conflict free access to several important subsets of an array. The address generation can be performed in constant time with simple circuitry. The skewing scheme can provide constant time access to rows, columns, diagonals, and N/sup 1/2/*N/sup 1/2/ subarrays of an N*N array with maximum memory utilization. Self-routing Benes networks can be used to realize the permutations needed between the processing elements and the memory modules. Two skewing schemes that provide conflict free access to three-dimensional arrays are also discussed. Combined with self-routing Benes networks, these schemes provide efficient access to frequently used subsets of three-dimensional arrays.>

A novel memory system is proposed for image processing. Latin squares, which are well known combinatorial objects, are used as the skew function of the memory system. A Latin square with desired properties for image-array access is introduced. The resulting memory system provides access to various subsets of image data (rows, columns, diagonals, main subsquares, etc.) without memory conflict. The memory modules are fully utilized for most frequently used subsets of image data. The address generation can be performed in constant time. This memory system achieves constant-time access to rows, columns, diagonals, and subarrays using a minimum number of memory modules.>

A new nonlinear skewing scheme is proposed for parallel array access. We introduce a new Latin square(perfect Latin square) which has several properties useful for parallel array access. A sufficient condition for the existence of perfect Latin squares and a simple construction method for perfect Latin squares are presented. The resulting skewing scheme provides conflict free access to various subsets of an N x N array using N memory modules. When the number of memory modules is an even power of two, address generation is performed in constant time using a simple circuit. This scheme is the first memory scheme that achieves constant time access to rows, columns, diagonals, and N1/2 x N1/2 subarrays of an N x N array using the minimum number of memory modules.