Abstract: A data acquisition system receives an analog input signal comprising a pllity of octavely-nested components including a base octave and a selected number of higher-level octaves, and transmits digital data words representative of each component over a channel. The data acquisition system includes a data transmission system and an interface. The data transmission controller generates transmission strobes signals defining a series of octave transmission cycles each associated with one of said octaves, each octave transmission cycle having a series of octave strobe states including at least one octave strobe state associated with the base octave and successively higher numbers of octave strobe states associated with successively higher-level octaves. The transmission strobe states associated with each octave are uniformly distributed during each octave transmission cycle.

Abstract: A hydrophone assembly for deployment on the bottom of a body of water is vided wherein a plurality of hydrophones are mounted in a spaced apart relationship about the circumference of a housing which is designed to hold signal processing electronics. Each hydrophone is constructed to detect a range of frequencies within a defined receive angle that extends outward from the circumference of the housing. A resonance absorbing material is interposed between the housing and the hydrophones to isolate each hydrophone from mechanical resonance. Tilt switches are connected to each hydrophone for automatically and independently selecting hydrophones to participate in the output of the hydrophone assembly based on the orientation of the hydrophones. Selected adjacent hydrophones define a continuous receive angle formed by combining the receive angle associated with each adjacent hydrophone. The continuous receive angle faces upward from the bottom of the water to include an angular portion of the surface.

Abstract: A multiplexing node is associated with each analog sensor of a line array. ach multiplexing node has an amplifier/filter section coupled to its associated analog sensor for amplifying and shaping a signal generated by the sensor. An A/D converter then samples the signal. A receiver is coupled to a previous one of the multiplexing nodes for receiving scrambled data and clock information in serial fashion from the previous node. A descrambler is coupled to the receiver to separate the data from the clock. A processor is coupled to the A/D converter and the descrambler. The processor time division multiplexes the data and clock from the previous node with the sampled signal from the A/D converter. The processor scrambles the so multiplexed data, clock and sampled signal. A transmitter is coupled to the processor to transmit the scrambled data, clock and sampled signal in serial fashion over a single data line.