Abstract: A torpedo countermeasure decoy which produces and broadcasts signals that e usually more attractive to a homing torpedo than those emanating from its intended target. Timely reset staircase generators combined with timely opened and closed gates generate stairstep signals which are added by a summing amplifier to produce a programmed composite signal thereof. A bank of voltage-controlled oscillators are driven by said composite signal in such a manner as to produce a predetermined plurality of discrete frequency signals within a predetermined plurality of consecutive but separated frequency bands within a given frequency spectrum, all of which are then effectively broadcast within the aqueous medium in the ambient environment of the torpedo's intended target--that is, the vessel to be protected.

Abstract: An underwater navigation device wherein a flux gate compass provides head difference signals, a doppler navigation sonar provides drift angle signals, which signals are combined by a summer to provide steering correction signals that are displayed by a steering null meter.

Abstract: An improved microphone assembly for use in a diver's mask or helmet and wh is characterized by a substantially flat frequency response at pressures from 1 to 30 or more atmospheres of breathing gas. A silicone rubber coated piezoelectric diaphragm is mounted by its periphery in a cylindrical housing with both sides of the diaphragm exposed to ambient gas pressures. A ground plate is mounted in said housing with one side in spaced relation to the diaphragm and having on the other side thereof a preamplifier and automatic gain control circuit electrically connected to the diaphragm and encased in waterproof potting compound.

Abstract: A pitch synchronized helium speech unscrambler is disclosed as including a air of bucket brigade analog delay lines which are timely and rapidly loaded with the electrical signal equivalents of human voice signals that are effectively supplied thereto by a receiving transducer. Said voice signal equivalents are then respectively unloaded more slowly from said pair of bucket brigade delay lines than they were loaded therein by a pair of different frequency clock generators driven in alternate successions by preprogrammed signals divided out from a master oscillator and in synchronism with a predetermined pitch portion of the speech signal received by said receiving transducer. The unloaded signals are then broadcast as acoustical voice signals by a transmitting transducer.