A data acquisition circuit is disclosed which provides sampled input voltage signals generated in a hostile environment to an input device, for example, the input circuitry of a computer. The data acquisition circuit provides electrical isolation to prevent damage to the input circuitry caused by electrical transients and short circuits occurring in the hostile environment and is particularly useful for sampling input data from thermocouples because it eliminates the need for an isolated power s...

Apparatus, and a related method, for fast carrier acquisition in a modem. The apparatus includes circuitry to speed carrier acquisition by the determination of which of two alternate phasors is being received during a baud synchronization period of a signal preamble before data transmission. Another aspect of the invention involves the use of a complex matched filter for the determination of the start of an equalizer training sequence in the signal preamble. The output of the matched filter exhi...

A data acquisition system is provided for acquiring acoustic information from an array placed in a body of water and for transmitting the information through a single transmission line to remotely located data processing equipment. The array includes a plurality of sensors, a plurality of sub-multiplexers, a master multiplexer and an A/D converter. The sensors are arranged to receive acoustic signals from objects submerged in the water and each sensor provides an analog electrical signal represe...

A device for digital acquisition, storage and processing of time-dependent data signals, especially for the accumulation of interferograms delivered by spin resonance and infrared spectrometers, comprises an A/D converter; a main memory having random access; a disk storage; a data channel connecting the A/D converter with the main memory which data channel contains a pointer register and a word counter and carries out the direct transfer of words delivered by the A/D converter to that area of th...

A marine seismic survey is disclosed in which a plurality of steerage centers are selected for circular traversal thereabout by a marine vessel towing a streamer cable. While the vessel and the streamer are following a circular track about a steerage center, the feathering of the cable creates a separate concentric track line for each of the mid-points between the receivers included in the cable and the source. In this manner an areal coverage is assured which requires no reliance on unpredictab...

Acoustic signals are received, selectively filtered, and digitally processed, e.g., by digitizing an amplitude, the peak of an echo, or the transit time, and the digital data are stored in a memory whose storage cells are associated with particular frequencies. Other acoustical signals are similarly processed but compared with the reference data to obtain a spectral representation of differences or ratios.

Microprocessor controlled electronically scanned collinear array receiver stem includes a dipole antenna mounted atop the array to provide complete scan coverage from horizon to horizon. The microprocessor controls the scan angle and the frequency range to provide full search coverage for all scan angles in a hemisphere. Simultaneous angle tracking and frequency tracking are accomplished when the desired signal is acquired.

The field locations of seismic shot points are chosen to produce partial multifold data, the static correction equations of which are at least partially coupled. The seismic cross sections resulting therefrom are substantially improved.

A flash beacon is described which uses a strong bright initial flash to attract attention followed by a series of weaker flashes to enable a person to easily locate the beacon source. The weaker flashes may be broken into code groups for identification or other purposes. An electrical circuit utilizing three capacitor banks interacting with each other, is described for operating the flash sequences.

An infrared acquisition device is described which surveys a relatively large field of view in which an emissive target is likely to appear. An optical system focuses an image of the target onto a mosaic of separate detectors arranged in concentric fields and so arranged that the appearance of the target image on the outer or peripheral field will reposition the optical system so as to move the image onto the inner or central field. Chopper means are provided for modulating the signal for process...