Abstract: An underwater speaker system having a pressure equalization system enabling the speaker to operate in its intended fashion over a wide range of water depths, e.g. from two feet up to sixty feet. Water pressure is applied to a diaphragm that forms one wall of a variable volume an internal face of a speaker membrane. Pressures are equalized on opposite faces of the membrane to enhance speaker performance.

Abstract: A speaking and hearing system for respirators, where the apparatus wearer is connected to a respiratory gas supply independent of the ambient air. A suppression, independent of acoustic signals, of the breathing noises of the apparatus wearer is provided by a switch device located in the respiratory gas line which reacts to the respiratory gas stream for the suppression of the breathing noises.

Abstract: An underwater communication system of the present invention comprises a transmitter including message inputting means having keys, each being assigned to each word, code converting means for converting a key input entered through the inputting means to a code assigned to the key input, modulator means responsive to the code for performing modulation, and transmit transducer means for converting an output of the modulator means to an acoustic wave, and a receiver including a receiver transducer means for reconverting the incoming acoustic wave from the transmitter to an electric signal, demodulator means for demodulating the electric signal to generate the code, speech synthesis means responsive to the demodulated code for producing a word corresponding to the code as a speech, and speaker means for outputting the synthesized speech.

Abstract: An underwater communicator device (10) is disclosed which permits acoustic communication with another diver by use of a voice synthesizer (42) cooperating with an acoustic transducer (40). A display (34A) is also provided to visually communicate the message. The keyboard (18) of the device (10) permits the diver to communicate stored messages by activating a single key 54 or to enter a complete arbitrary message by keying in the actual message. In other forms, the device (10) can include an air pressure transducer (60) for monitoring air tank pressure with a warning of low pressure. A depth pressure transducer (64) can be incorporated into the device (10) to monitor the depth of the device and diver. A bottom timer can be incorporated within the device for measuring the time of the depth. These functions can be continuously displayed to the diver on display screen 34B.

Abstract: An underwater voice communicator in which the preferred embodiment comprises a pair of tapered tubes in communication with a diver's mouth. The tubes are constructed of a material having a sound impedance similar to the sound impedance of water. Sound energy issuing from the mouth of a diver is reflected down the length of the tapered tubes to an area of the tube that concentrates the sound for injection into the surrounding water.

Abstract: A waterproof pouch to house a personal stereo cassette tape player or radio electrically connected by means of a retractile cable to a pair of waterproof headphones. The waterproof pouch has a closure enabling the pouch to repeatedly be hermetically sealed and reopened. A tubular belt loop is attached to one side of the pouch and secures a belt and buckle combination which fastens around the user's waist. A connector permanently and hermetically secures the electrical cable extending from the exterior to the interior of the pouch. The electrical cable in a coiled retractile form extends from the connector and splits into a Y-shape with both legs electrically attached to the waterproof headphones. Both waterproof headphones consist of a rigid disc with a waterproof earphone mounted on one side and a bracket mounted on the opposite side such that an elastic headband extends through the bracket. The headband is adjustable in length and secures the headphones to the user's head.

Abstract: An undersea communications system provides for improved data transmission pabilities. Two separate sources of information respectively modulate the upper and the lower sidebands of an acoustic carrier. The discretely modulated sidebands are simultaneously transmitted without the acoustic carrier or the acoustic carrier can be added to allow asynchronous or synchronous demodulation and use of the two modulating informations. Separation of the information in the two discretely modulated sidebands is assured by shifting the modulating information to ultrasonic regions and filtering out upper and lower sidebands of modulating information. Next, the shifted sidebands are modulated by an acoustic carrier which, optionally, is transmitted along with the discretely modulated upper and lower sidebands. A phase locked loop in the receiver portion assures synchronous demodulation or a crystal oscillator allows asynchronous demodulation of the discretely modulated upper and lower sidebands.

Abstract: An apparatus and method of transmitting and receiving information underwa assure improved performance characteristics. Modulating a carrier and appropriately filtering it allows the transmission of only single sideband signals or a carrier along with single sideband signals to increase the range at reduced power consumption levels. Demodulating incoming signals can be done synchronously (when the carrier is present) or asynchronously (only single sideband signals) to extract the information. When a number of carriers are modulated and, simultaneously, are transmitted and received, the system's reliability is enhanced.

Abstract: The invention relates to a novel helium-speech unscrambler which can be located at a diver's location, and enables the helium-speech voiced by the diver to be subjected to waveform time expansion to reduce the bandwidth of the helium speech (e.g. to 2 to 3 KHZ) prior to transmitting the speech signals to a distant location on a carrier wave selected for optimum transmission through the water.

Abstract: A bi-directional underwater communication system provides a submerged operator with the capability to communicate with a surface site. A face-mask-mounted microphone and an earphone are connected to a submerged, watertight radio. The radio antenna cable is carried by a buoy to the surface of the body of water in which the operator is submerged.

Abstract: Audio communications between divers or between a diver and a surface craft are made without unduly burdening the divers. Diver carried throat microphones pass vocal signals to a preamplifier-amplifier package. The package drives a transducer which projects amplified vocal signals that are capable of being heard by the other diver or feeds signals to a surface power supply pack and a speaker while a surface microphone enables communications from the surface to the divers. The divers don't carry any additional electronics instrumentations and, since there is no signal heterodyning, distortion is reduced.

Abstract: An acoustic transmission system for a gaseous or liquid transmission medium, in which the transmitting apparatus double-sideband amplitude modulates a carrier with the signal to be transmitted, the double-sideband amplitude modulated carrier is radiated acoustically over the transmission medium, and the receiving apparatus receives the modulated carrier plus noise introduced in the medium, rejects the superimposed noise by sampling and reconstruction means, and delivers the modulated carrier substantially free from superimposed noise.

Abstract: 2. A method by which a submarine while deeply submerged in the sea may receive a message from a remote station without disclosing to others the position of the submarine, which comprises transmitting from said remote station into the atmosphere message information modulated on electromagnetic radiant energy, intercepting said radiant energy at a plurality of separated and widely dispersed relay stations on the surface of the sea, extracting the message information from the electromagnetic energy and transmitting acoustic wave energy modulated by said message information from each of said relay stations into the sea, locating said submerged submarine in message receiving range of one of said relay stations and detecting the acoustic wave energy modulated by the message information aboard said submarine.