Abstract: An analog-to-digital converter is disclosed providing high speed operation or high resolution analog signal data. The converter utilizes the repetitive nature of the data by converting a portion of the signal corresponding to the changing component of the data. A smaller number of bits of information is thus converted from analog-to-digital form than is needed to represent the data. In addition to savings in hardware, a significant saving in conversion time is provided. The cancellation of static components of a radar signal moreover provides, within the system, a clutter-free signal.

Abstract: A digital computing method and apparatus for complex numbers which, more particularly, comprises a technique and hardware for forming the complex linear vector product of two transformed sequences. The invention is designed for use in a computer system wherein all arithmetic is performed modulo a number of the form 2.sup.b +1 and, in essence, consists of replacing complex numbers of the form A+jB by numbers of the form A.+-.2.sup.b/2 B, after which products, sums and differences are computed to yield the desired result.

Abstract: A method and apparatus for modifying data which is stored in a medium of hival quality. The original data is left unmodified, and a modification document is prepared which has addition and deletion data thereon. The original and modified data is combined in a given way to generate a correctly modified composite.

Abstract: A system, preferably a pulse echo reflection system, for residual tire life prediction by ultrasound includes: a transmitter transducer; means to provide pulses of electrical energy to the transmitter transducer, that converts the electrical pulses into pulses of ultrasonic vibrations and transmits them into an area of the plycontaining portion of the carcass of a tire, having a number of plies in the carcass, to be tested; clock means to control the frequency of the electrical pulses; a receiver transducer mounted relative to the transmitter transducer to receive ultrasonic energy reflected by the tire; amplifier means connected to the receiver transducer to receive reflected ultrasonic energy from different levels within that portion of the carcass of the tire, including reflected ultrasonic energy from plies of the carcass of the tire; processing means having an input connected to the amplifier; and gate means responsive to the clock means to provide, after a delay following each electrical pulse, a time-g