Abstract: A non-impact printer has a movable printhead carriage for traversing a print medium and has a bracket, also serving as a heat sink, pivotally connected to the printhead carriage. A non-impact printhead is secured to the bracket and positioned to contact the print medium. A spring is positioned between the bracket and the printhead carriage to move the bracket and consequently the attached printhead into contact with the print medium. A printhead adjusting eccentric, causing relative motion between the printhead carriage and the bracket, enables vertical positioning of the printhead with respect to the print medium.

Abstract: A sweep generator for a seismic source vibrator provides for any one of a variety of sweep signals governed by input parameters. Selected analytic functions may be entered which are solved to provide a plurality of sweep parameters. The sweep parameters may also be directly entered by the operator. The time and frequency sweep parameters (or time and amplitude) are then employed to generate polynomial coefficients for consecutive use in a polynomial equation. The polynomial equation is repeatedly solved to generate a series of instantaneous frequencies or instantaneous amplitudes which are applied to an analog wave synthesizer. The analog wave synthesizer then generates an approximation to the desired sweep signal for input to the hydraulic system of the vibrator.

Abstract: A paper web-moving system includes a friction-type drive roll mechanism cooperatively operating with a detachable tractor drive mechanism. In one embodiment, the paper first passes over and engages a pair of driven tractors at an angle with respect to the horizontal, then under a driven roller platen and between two spaced apart sets of rollers positioned to force the paper against the roller platen. The drive mechanisms are configured so that the paper drive rate of the roller platen is greater than the drive rate of the tractor, causing paper tension therebetween. The present system permits the use of friction roll paper, tractor fan fold paper, and single sheets with a short tear-off capability.

Abstract: The thermal printhead of a printing terminal requires a controlled voltage to insure uniformity of the print copy. Printhead temperature is sensed by a voltage generating diode on the printhead itself. This feedback voltage is used to control the reference voltage of a switching regulator power supply which in turn provides power to the thermal printhead. The switching regulator comprises an efficient means of providing a controlled voltage to the thermal printhead.

Abstract: A general purpose array processor is made up of a plurality of independent processing units. A digital host computer provides the overall control for the system. An interface unit is connected to receive instructions and data signals from the host computer and then to autonomously and selectively distribute the instructions and data to other units within the system and to transmit status, control and data signals to the digital host computer. A transfer controller unit is connected to a bulk memory and to the interface unit for receiving the instructions from the interface unit and for autonomously and selectively transferring data signals from the bulk memory means to an arithmetic unit which is also connected to the interface means and receives instructions therefrom for subsequently autonomously and selectively performing arithmetic functions on the data transferred by the transfer controller unit. An input controller unit may be provided for receiving data from a data source.

Abstract: An impact printer has a flux regulator for each of the coils in its printhead. Each regulator provides a reference voltage indicative of the desired flux in the associated coil. A circuit is provided for measuring the flux in the coil and for providing a voltage representative thereof. The measured flux representation is compared with the reference flux representation and any difference is applied to a power circuit which then provides more or less power to the associated coil.

Abstract: An electronic system automatically detects significant events in a seismic trace. The seismic trace is defined as a series of consecutive points, equally spaced in time. The system provides for taking the Nth derivative of the trace at each of the points. The system has the capability of identifying the time of the zero-crossings of the Nth derivative and of establishing the amplitude of the trace at the time of the zero-crossing of the Nth derivative. Memory is provided for storing the amplitude of the trace and the times of the zero crossings in the Nth derivative. Finally, displays are provided for displaying the traces and the zero-crossings in the Nth derivative as a hard copy of visual display.

Abstract: A method of reducing Rayleigh waves (ground roll) in land seismic exploration employs a unique combination of amplitude output from and spacing of the vibrator sources making up a land seismic exploration system. The velocity of the Rayleigh wave for the prospect to be explored is determined. At least one receiver is used and is spaced from the vibrator sources a distance sufficient to establish the receiver as being in the far-field. The output of each of the vibrator sources is locked in phase and frequency and known separations between the vibrator sources are maintained. The frequency is varied and the individual output amplitude of each vibrator source is varied at each frequency so that the resultant Rayleigh waves traverse the known separations resulting in out-of-phase Rayleigh waves between the sources.

Abstract: A bi-planar pontoon paravane is towed by a marine vessel and controls the depth and position of a towed seismic source array. The bi-planar pontoon paravane is made up of a buoyant bridge with right and left wings attached to the long sides of the bridge, the wings projecting into the water and, in concert, providing a side force. The paravane is towed by a tow line connected to an adjustable bridle which in turn is connected to the paravane. Remote adjustment of the bridle is provided by an hydraulic valve on the vessel controlling an hydraulic motor and gear arrangement on the paravane to adjust the bridle. Adjustment of the bridle adjusts the angle of attack of the paravane. The paravane provides a housing formed below the bridge and between the two wings for housing the seismic source array. A boom on the vessel is attached to the seismic source array, through the bridge, when the assembly is to be placed in or removed from the water.

Abstract: There is disclosed a method for constructing and displaying tree structures with automated data processing equipment. A focused view of a portion of the tree is provided to enable an operator to perform editing and evaluating functions on the tree. The focused view presents a view of this portion of the tree structure with a geometry different than what would be used if the entire structure were to be portrayed. This provides a view with sufficient resolution to be highly readable. In the preferred embodiment, the focused view is comprised of a focus node of the tree, its parent node along with the branch connecting the parent node and the focus node, the sibling branches of the connecting branch, all successor nodes of the focus node, and the branches connecting the successor nodes to the focus node.

Abstract: A computer system reviews and modifies horizons tentatively defined by a network of pairs of turnings. The curvature for each of the paths of turnings of the network in both the X and Y directions is assessed. If the curvature exceeds a predetermined value in any of the paths, that path is terminated at the point of excessive curvature. Also, each pair of turnings is tested to determine whether it is in a closed loop made up of four turnings which in turn make up four pairs of turnings to determine that there is three-dimensional continuity. The horizons are thereby modified if modification is required.

Abstract: A tilt and height adjustable display stand has a display mechanism connected to a base through a series of interconnecting linkage arms. A tilt gas spring and a height gas spring are interconnected within the linkage in such a manner as to offset the weight of the display mechanism when the display mechanism is tilted or moved vertically.

Abstract: A computer system displays, in two dimensions, a representation of a three-dimensional volume. The three-dimensional volume representation is a tessellation of cells, represented as three-dimensional units. The three-dimensional volume is represented by a plurality of digital numbers. A designator designates which of the digital numbers are to be represented in the two-dimensional display. Each digital number is represented by one cell. Also, each digital number represents a color. Each corresponding cell is colored in accordance with the digital number. A designator designates which of the digital numbers is to be represented by a cell in the three-dimensional representation. A cursor, controlled by a mouse, may be used to indicate which of the three-dimensional volume representation is to be excavated by indicating at the appropriate cells and then electronically ordering the excavation.

Abstract: A transportable hydraulic seismic transducer has a seismic energy source connected to a pad for imparting elastic waves to the underlying ground. The energy source has a reaction mass with a single diameter cylinder formed therein, a double ended piston reciprocally mounted in the cylinder with a piston rod extending from opposite ends of the piston and a pair of bushings fitted within the cylinder at opposite ends to provide bearing surfaces for the opposite ends of the piston rod. A piston may be ringed and a liner fitted into place within the cylinder with the rings forming a seal with the liner. The piston may also be ringless and a liner made of a bushing material fitted within the cylinder so that between the piston and the liner, an adequate seal is provided. The use of the single diameter cylinder or bore permits the total machining of inserted parts such as the bushings and liners to be done before inserting in the reaction mass bore.

Abstract: A computer system extracts horizons, each defined by a network of points in a first format from within a three-dimensional volume. Each point is tagged with a plurality of parameters including links in the X and Y direction for interconnecting the points. The system accesses any one of the points in the network then accesses every point that is linked directly or indirectly to the first accessed point. An address pointer is established for each of the accessed points, to define a second format. A second format is in a two-dimensional array and any point that is accessed a second time is rejected to prevent any spiraling of the horizon. The second format may be stored and displayed.

Abstract: A vibrator seismic source has a sweep generator for providing a pilot signal and sensors for generating a feedback signal representative of the force imparted to the ground by the vibrator pad. Circuitry is incorporated for separating the fundamental signal from the feedback signal and for separating the distortion from the feedback signal. Means are provided for generating a control signal for controlling the action of the vibrator means. Included are means for reducing the amplitude of the pilot signal a designated amount, determined by the distortion, and means for algebraically summing the reduced amplitude pilot signal and the fundamental signal to provide an error signal. The error signal is input to a loop filter to perform real time correction of the control signal. The reduced amplitude pilot signal is input to means for adjusting the control signal for trends in the distortion.

Abstract: A vibrator seismic source has a hydraulic system, including a pad, for applying reciprocating forces to the ground and sensor means for generating a feedback signal representative of the force applied to the ground. Circuitry is provided for generating a pilot signal representative of the desired force to be applied to the ground. The pilot and feedback signals are single sideband shifted to increase both frequencies by a predetermined frequency. The high frequency pilot and feedback signals have their phase difference conventionally detected and provided to a digital computer for phase shifting the signal for controlling the vibrator so that the feedback signal is in phase with the pilot signal. In another embodiment, the instantaneous phase of each signal is computed continuously by a digital computer. The control signal digital representation is corrected to correspond with the pilot digital representation and an analog output signal is generated to provide the proper analog control signal.

Abstract: The present invention relates to a video display controller system which permits a variety of differing video attributes for each displayed character. A character code is stored in a character memory and an attribute code is stored in an attribute memory at corresponding memory locations for each display position. In accordance with the present invention the transfer of data to and from the attribute memory is through an attribute latch. Each time a character is written into the character memory the attribute stored in the attribute latch is stored in the corresponding location in the attribute memory. Similarly, the attribute stored in the corresponding location of the attribute memory is stored in the attribute latch upon reading a character from the character memory. The attribute latch can be independently read out or written into. This technique is advantageous for specifying a display screen in which many characters have the same video attribute and for executing block moves within the display screen.

Abstract: An enclosed, electronic system has a plurality of lower power-dissipating electronic components mounted on a chassis. The components are positioned adjacent each other to form low volume fluid ducts therebetween. A low volume fluid duct is formed between one side of the plurality and one end enclosure of the system. At least one higher power-dissipating electronc component is also mounted on the chassis, forming a high volume fluid duct between one of its sides and one side of the last of the lower power-dissipating electronic components, and a high volume fluid duct also formed between the other side of the higher power-dissipating electronic component and the other end enclosure. Air is caused to blow through the low volume fluid duct and then to be exhausted through the high volume fluid ducts. The rate of air flow through the high volume ducts is one half of the minimum required to cool the higher power-dissipating component.

Abstract: An optically activated keyboard provides inputs to a digital computer or the like. The keyboard includes a key housing having formed therein a wave guide matrix of intersecting columns and rows with light emitting diodes (LED's) installed in one end of each column and photo transistors installed in one end of each row. A plurality of keys are mounted at the top surface of the housing, each key having a plunger which projects through a corresponding aperture in the housing, when the key is depressed. The intersections of the columns and rows are located directly beneath the apertures so that when a key is depressed, its plunger intrudes into the volume at the intersection. Each plunger, in concert with the wave guide intersection, forms a light polarizing system. In the preferred embodiment, each plunger has a reflecting face that is angled to reflect light from the LED in the corresponding column into the corresponding row, finally impinging against the appropriate photo transistor.