Abstract: A serial binary multiplier receives a multiplicand and a multiplier, and produces a product. The multiplicand is received in a serial format beginning with a most significant bit and ending with a least significant bit. The multiplier is received in a parallel format, and the product is available in both serial and parallel formats. The multiplier consists of a multiples generator, an arithmetic unit, and a decoder. The multiples generator generates a multiple of the multiplicand for each bit of the multiplier that is equal to logic one. The multiples generator produces the multiples in a serial format beginning with a most significant bit and ending with a least significant bit. The arithmetic unit serially receives the multiples produced by the multiples generator, and produces the sum of the multiples. The sum is produced in the form of two serial binary numbers which compose an unsigned redundant binary number. The decoder receives the unsigned redundant binary number produced by the arithmetic unit.

Abstract: The elevation angle of a low angle target is accurately measured by subtracting from the received radar signal signals derived from an estimated value of target elevation which reduces the resulting signal to a minimum. The estimated value is an accurate measure of target elevation.

Abstract: An underwater viewing system described herein substantially reduces the number of hydrophones in the receiving array and associated circuitry by providing a plurality of transmitting transducers spaced apart by a known distance, each emitting a coded output which is normally a separate frequency. The receiving array, which is preferably square or rectangular, includes a substantial number of receiving hydrophones.A synthetic aperture technique is applied in which the reflected signal arriving at each individual hydrophone is amplified, modulated with a lower frequency reference signal, filtered, digitized and stored in a memory, preferably as part of a computer. The computer also compares each digitized hydrophone signal against sine and cosine reference signals at each frequency and performs a Fourier analysis of each row and column to reconstruct a primary image.