Abstract: An improved cableless seismic digital recording system is disclosed which records seismic-trace data generated by any type of seismic source, including high energy impulsive seismic sources, such as dynamite, and low energy surface seismic sources, such as vibrators and hammers. A seismometer, or geophone, is connected to a remotely deployed radio-controlled portable recorder which contains circuitry for sampling, digitizing, processing, storing, and recording seismic-trace data. Coded radio signals instruct each recorder to commence an operation or sequence of operations from a predetermined set of programmed instructions stored in program read only memory included in each recorder. Such operations include seismic-trace data acquisition; optional weighting and vertical stacking (summing); normalization; recording; and seismic source initiation.

Abstract: 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 with the swept frequency vibrators for developing signals representative of reaction mass accelerations and baseplate accelerations, and means for monitoring the swept frequency vibrator's pilot signal. The system also includes a signal calculating means for determining vibrator operating characteristics from the pilot sweep signal, reaction mass acceleration signal, and baseplate acceleration signal and processing means for processing the vibrator operating characteristics to obtain analysis characteristics for evaluating and adjusting the performance of the swept frequency vibrator. In operation, the present invention provides a method for analysis characteristics to analyze and adjust the performance of swept frequency vibrators in real-time on location.

Abstract: A method for recursively, continuously estimating the noise and signal components of a seismic trace. More particularly, a method for suppressing the noise component in seismic data so as to enhance the resolution of seismic events contained therein. The signal component of each seismic trace is determined recursively from the preceding estimate of the signal component in each preceding seismic trace.

Abstract: A data transfer system is disclosed for a computer system which includes at least one processor, a memory coupled to the processor, and two direct memory access selector channels. A hardware interconnection is provided between the two selector channels such that they can be used to transfer data from one portion of the memory system to another directly, using direct memory access techniques, without intermediate mass storage. The disclosed software provides a transfer system which mimics the use of magnetic tapes in many respects in order to simplify use of the system.

Abstract: A system for testing seismic signal recording equipment wherein a test signal is generated which simulates the output of at least one seismic sensing device, and, thereafter, the test signal is applied to the seismic signal recording equipment. The test signal is recorded by the seismic signal recording equipment and the recorded signal is compared with the generated test signal to evaluate the performance characteristics of the seismic signal recording equipment. The system can include circuitry to vary component elements of the test signal to test different performance characteristics of the seismic signal recording equipment, as well as ability to generate a random noise signal for addition to the test signal.

Abstract: This disclosure describes a decoding system for decoding and formatting digital data recorded on magnetic tape in the STR ("speed-tolerant recording") format. The digital words are stored in cells of about equal width except that the leading cell of each word, called a "sync" cell, is of double width. Each cell starts with a positive pulse, and a cell detector provides a signal each time this occurs. The apparatus includes a data detector, which analyzes the width of this positive pulse relative to the cell width to determine whether the cell is a 1 bit or a 0 bit. Since the measurement is relative, cell length, i.e., total cell time, is not important. The bit determination is loaded into a shift register. Other apparatus determines the width of the cell, so that a sync cell detector can determine whether a sync cell is present or not. When a sync cell is detected, a pulse is generated which actuates the output buffer register to load the bits from the shift register. Data flows from buffer to a computer.

Abstract: The analog signals provided by a seismic-velocity well logger, resulting from the transmission of seismic impulses from a transmitter to a receiver in a logging sonde in a well by paths that include travel through the rock walls of the borehole, are digitally recorded. These seismic impulses and the resulting received seismic signals, or traces, are repeated approximately 20 times per second. The recording apparatus digitizes these analog traces by determining signal amplitudes at intervals of approximately 10 microseconds and temporarily stores the digital values. The apparatus includes a programmable-gain amplifier, an analog-to-digital converter, a computer, and a memory in which are, in addition to the data, also stored the values of gain which are to be used in digitizing the next signal. That is, on each digitizing interval a stored gain "program" is read out of the computer and sets the gain of the amplifier.