Abstract: A mobile magnetometry processing system which scans an area in order to mure the magnetic field strength over the area, comprising:a plurality of N sensors for sensing the magnetic field of the area being scanned, each sensor generating an output signal, for example, a voltage, which is a function of the magnetic field it scans, the sensor being aligned in the general direction of the motion of the system;a plurality of N sets of means for weighting, for receiving and weighting the N signals from the means for sensing, each of the N sets comprising M weighting means;a plurality of M summers, each have N inputs, one from each of the N sets of means for weighting, for summing its N input weighted signals;a plurality of M filters each having an input which is connected to the output of a summer, for delaying the exit of an input signal by an amount of time equal to the time required for a sensor to advance the distance to the nearest adjacent sensor, the filtering process comprising a convolution;means, associat

Abstract: A secure communication system, which may be safely used even in the prese of an enemy interceptor, includes a transmitter and a receiver.The transmitter comprises a first modulo-2 adder, having as one input a sequence of N-bit binary numbers. A first random read-only memory (ROM), comprises a plurality of storage cells. The input of the ROM is connected to the output of the modulo-2 adder. Each of the cells of the ROM, which have distinct addresses, contain a random number, with no two cells containing the same random number. The input to the ROM is a binary number representing a specific address, whereas the output of the ROM is a signal representing a random binary number. A delay line has its input connected to the output of the random read-only memory, its output constituting the second input to the modulo-2 adder. A second random ROM, having the same type of hardware but different random content, has its input connected to the output of the delay line.

Abstract: An apparatus, using three gradiometers, measures the spatial variation of a agnetic field along a path of motion of the apparatus. The apparatus comprises three gradiometers oriented along the mutually orthogonal axes, x', y' and z' defined on the moving platform. The outputs of the gradiometers are the gradients of the magnetic field when the motion is considered to be in the y' direction. Three filters, each having an input connected to the output of one of the gradiometers, are constructed to have an output signal which has a relatively narrow positive peak with a relatively wide negative area on each side of the peak. The net area is approximately zero when the input to the filter is a doublet. Three squares, each having an input connected to the output of a filter, square their input signals. A summer, having three inputs connected to the outputs of the squarers, obtains the sum of the squares of the high-pass filtered components x', y' and z' of the magnetic field.