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8797830 Explosion-proof acoustic source for hazardous locations  
An explosion-proof system for generating acoustic energy. An exemplary embodiment of the system includes a main housing defining an open housing space and an opening. A cover structure is...
8588030 Reducing noise in seismic surveying environment  
In one embodiment of the invention a method includes (a) operating a combustion engine at a first activity level corresponding to a first noise level; (b) charging an accumulator with a first...
8375560 Method for manufacturing a condenser microphone  
A method for manufacturing a condenser microphone includes forming a diaphragm module using microelectromechanical system (MEMS) techniques. The diaphragm module includes a diaphragm that is...
8371416 Constant holddown weight for vibratory seismic sources  
The invention relates to maintaining constant holddown force on the vibrator baseplate during actuation. The invention described measures the weight on the point of locomotion verses the baseplate...
8134891 Apparatus for generating a seismic source signal  
A seismic source signal generator having feed-forward control uses pressure, current, and/or valve position sensors to detect system component parameters. Initial and operating parameters are...
7987943 Apparatus and method for generating a seismic source signal  
A seismic source signal generator includes a mass, a primary accumulator and a secondary accumulator, the secondary accumulator having an internal volume smaller than an internal volume of the...
7974154 Vibroseis calibration technique and system  
A technique includes operating a seismic vibrator, including driving the seismic vibrator at different frequencies and driving forces. The technique includes monitoring a parameter affected by the...
7974152 Control system for marine vibrators and seismic acquisition system using such control system  
A method for controlling output of a marine seismic vibrator includes operating the vibrator using a predetermined driver signal. A vibrator output signal is measured at at least two different...
7929380 Apparatus and method for generating a seismic source signal  
A seismic source signal generator having feed-forward control having pressure, current and/or valve position sensors that detect system component parameters. Initial and operating parameters are...
7859945 Efficient seismic data acquisition with source separation  
A method for the simultaneous operation of multiple seismic vibrators using unique modified pseudorandom sweeps and recovery of the transmission path response from each vibrator is disclosed. The...
7841444 Seismic vibrator baseplate  
One example of a seismic vibrator system includes a baseplate having a bottom surface and a coupling mechanism, the coupling mechanism being operable to a deployed position; a hold-down mass...
7628248 Apparatus and method for generating a seismic source signal  
A seismic source signal generator includes a mass, a primary accumulator and a secondary accumulator, the secondary accumulator having an internal volume smaller than an internal volume of the...
7519480 Driving-force output of a reciprocating actuator  
The force exerted by a reciprocating actuator is estimated as a weighted sum of three quantities: a reaction-mass acceleration, a baseplate acceleration, and a relative acceleration of the...
7364008 System for imparting mechanical impulse energy to the ground  
The invention relates to an apparatus and method for imparting a precise amount of impulse energy to be delivered to the ground. The apparatus includes an anvil for operative deployment against...
6460803 System for control of active system for vibration and noise reduction  
An adaptive controller is used to adaptively generate vibration cancellation signals driving a controlled device which effects an associated vibration and noise-producing plant. The adaptive...
5412623 Multivibrator waveform monitoring system  
A multivibrator waveform monitoring system uses a plurality of seismic energy sources for giving vibrations to strata and a prospector, connected to a geophone, for measuring reflected vibrations....
5410517 Method for cascading sweeps for a seismic vibrator  
A method for cascading or linking seismic vibrator sweeps to form a cascaded sweep sequence. According to the method, a first cascaded sweep sequence is generated containing N sweep segments...
5400299 Seismic vibrator signature deconvolution  
A method for processing seismic vibrator data. The method utilizes a deterministic signature deconvolution of the vibrator data to compress the impulse response of the data resulting in sharper,...
5331607 Sweep frequency vibrator  
A sweep frequency vibrator is set forth. It has an elongate cylindrical housing closed at the top and bottom ends. On the interior, there is a reactionary mass fixed to identical upper and lower...
5128908 Pressure feedback servovalve for a seismic vibrator  
An apparatus for reducing harmonic distortion and causing a more linear response in a hydraulic vibrator apparatus which generates a seismic signal into the surface of the earth is disclosed. The...
5117926 Method and system for controlling vibrations in borehole equipment  
Vibrations in borehole equipment are controlled by defining the energy flow through the equipment as the product of an "across" variable and a "through" variable, wherein fluctuations in one...
4980874 Method and apparatus for maximizing seismic shear wave production  
An apparatus and method for maximizing the shear wave energy imparted into the soil upon the impacting of a base plate by an impact mass from a seismic generator. A seismic generator is disposed...
4930113 Suppression of air-coupled noise produced by seismic vibrators  
Air wave noise caused by a vibrating baseplate on a seismic vibrator is reduced or eliminated through active cancellation of sound. In active cancellation, the detection of acceleration of the...
4855967 Seismic vibrator hold-down weight monitor/controller  
The disclosure relates to a seismic vibrator having an airbag isolator, a transducer for monitoring the instantaneous air pressure within the airbags, a summer to add the pressures within each air...
4821246 Electromagnetic vibrator for seismic and civil-engineering applications  
An electromagnetic vibrator for seismic and civil-engineering applications is provided with a supporting structure fitted with a coupling element, and a reaction mass, which is to be caused to...
4785431 Broad-band hydraulic vibrator  
A hydraulic vibrator having an adjustable piston rod and a fixed piston rod to vary the cylinder volume for operation at different vibration frequencies. The adjustable piston rod is in threaded...
4782446 Vibrator quality control method and system  
A field quality control system and real-time method for evaluating the performance of swept frequency vibrators is provided. The system includes independent sensing means adapted to be mounted...
4779243 Transducer array velocity sensor and processor system  
A differential transformer is used as a feedback sensor for generating an error signal sensed at the face of an element of a sonar transducing array. This error signal is used to correct the...
4766576 Seismic source vibrator having improved sweep generator  
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...
4751687 Methods of reducing harmonic distortion in continuous wave seismic exploration  
Described is a method of driving a seismic vibrator with a control signal to produce an output signal having minimized harmonic distortion. The method includes the steps of producing a plurality a...
4750157 Seismic vibrator earth impedance determination and compensation system  
An earth impedance determination and compensation system for use with a seismic vibrator utilizes output signals from accelerometers on the baseplate and reaction mass portions of the vibrator to...
4723231 Source tunable array for ground roll reduction  
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...
4706231 Reaction mass acceleration feedback device  
An improvement for the drive control system of a vibratory sound source used in seismic exploration comprising apparatus for generating a feedback signal proportional to the instantaneous...
4692912 Automatic force control for a seismic vibrator  
The present invention provides a method and apparatus for controlling the response of a seismic vibrator during its actuation period. The sweep input signal is modified in response to an average...
4670863 Vibrator seismic source having adaptive distortion limiting control system  
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....
4654836 Seismic vibrator source having improved phase detector  
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...
4637002 Seismic source vibrator having self tuning controller  
A self-tuning controller, for dynamic control of the servo valve and the actuator (mass, column, pad) of a seismic source vibrator, includes a state variable feedback network associated with a...
4616352 Vibrator seismic source having distortion limiting control system  
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....
4567583 Adaptive preset force level control for a seismic vibrator  
A seismic vibrator for shaking the ground is driven by an input sweep signal. A control signal, which is a function of the output force level of the vibrator, modulates the sweep signal to limit...
4564927 Method and apparatus for testing seismic vibrators  
A method of seismic exploration, wherein one or more vibratory sources are employed to generate an input signal whose frequency varies as a function of time and wherein the signal is reflected and...
4538203 Passive mass-spring type of sensing device having electronic damping  
A passive mass-spring type of sensing device or other such device for monitoring a particular parameter, for example mechanical vibration, is disclosed herein. This device utilizes an electrically...
4537077 Load dynamics compensation circuit for servohydraulic control systems  
A load dynamic compensation circuit for a servohydraulic control system for fixtures and specimens being tested operating in various degrees of freedom, for example in an environment to simulate...
4519053 Force or pressure feedback control for seismic vibrators  
A seismic vibrator source having an hydraulic vibrator coupled to vibrate a ground pad is provided with one or more force transducers such as, for example, load cells, strain gauges, or...
4516230 Protective drive-level limiter for an electro-hydraulic vibrator  
In accordance with an embodiment of this invention, voltages are received from the pilot valve torque motor, the main servo valve and the actuator indicating the value of the torque motor current,...
4500976 Seismic exploration  
In a seismic exploration system, the waveforms provided from a plurality of seismic sources are phase shifted so as to maximize the strength of signals received by a plurality of seismic receivers...
4173749 Digital drive and phase-lock for seismic vibrators  
This invention concerns a synchronizing control for an electro-hydraulic seismic vibrator, which control utilizes a magnetic tape cassette reader that puts out a train of pulses of changing time...
4095425 Control system for rotary air modulator  
A control system for providing precise speed control for a rotary air modulator, and particularly for providing synchronized speed control as between two or more rotary air modulators. A common...
4068210 Seismic vibrator phase detector  
A phase detector for detecting the phase difference between a pilot reference signal and a feedback signal generated by movement of a vibrator baseplate. The detector includes a phase shifter for...
4063613 Control means for pressure fluid vibrators for generating seismic waves in the earth  
Improvement in electro-fluid vibrator means used for generating seismic waves in the earth in which the flow of pressurized fluid to the vibrator is controlled in accordance with the resultant...
4064481 Vibrator and processing systems for vibratory seismic operations  
Method and apparatus for carrying out vibratory seismic operations and processing seismic records, involving generating a square wave analog sweep signal for driving a vibrator, generating a...

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