Abstract: A sensor for sensing the location of objects buried in the loose sediment in the bed of the sea. A hollow, cylindrically symmetric, conductive shell is used to inject current into seawater at its tips along its axis. A sensor coil oriented along the axis ignores all magnetic fields except those along the axis, and is used to measure return signals. This is particularly useful in detecting dielectric objects buried in the sediment and in rejecting motion relative to the seabed.

Abstract: An decoding system for transmitting a signal through a noisy, unstable, mipath environment, in which the signal consisting of eight possible symbols is encoded using four of eight possible frequencies in an orthogonal Hadamard matrix, transmitted through the environment, and decoded using the same orthogonal Hadamard matrix, thereby providing a correlation result which can compensate for at least one error in the received signal for each symbol.

Abstract: The operational amplifiers conventionally used in electronic analog compus can be replaced with fixed-gain differential amplifiers having no external negative feedback to control their gain. This allows a large increase in the bandwidth of the computers, with a resulting faster response time. Circuits for summing, integration, and differentiations are specifically disclosed using fixed-gain amplifiers.

Abstract: An improved electrically controlled thermotropic liquid-crystal heat valve to control the flow of heat between two bodies of different temperatures by interposing therebetween a fluid layer of liquid-crystal material having a nematic temperature range that includes the temperature of both bodies. This type of heat valve has particular application to any free-swimming divers' diving garments, to provide some thermal protection against the cold ambient water. The heat valve uses stable liquid-crystal materials encapsulated in a sealed environment, with the valves' electrodes being shielded and not in direct electrical contact with the liquid-crystal material. This arrangement essentially completely eliminates the electrochemical effects which can otherwise degrade the liquid-crystal materials, so that the liquid crystal may function for a very long time.

Abstract: An optical storage device having a mass storage medium which remains stationary as data is transferred by a laser. The stationary mass storage medium permits rapid data transfer since delay due to rotation of the medium, as in a compact disk, is eliminated.