A minicomputer-oriented geophysical data acquisition system has been developed which offers simplified system operation, instantaneous floating point capability, and provisions for real-time quality control. The computer performs all routine tasks with the operator interacting only to begin or modify major functions. The system is designed to fully utilize the precision capability of the floating point format in both its acquisition and processing capacity. Special features allow quality control to be applied to the data during acquisition.
A geophysical seismic data acquisition system has been developed which simplifies data collection while monitoring data integrity and which allows full precision on-site processing. This advanced system brings the digital recording format, including instantaneous floating point amplification, together with a minicomputer to provide improvement in data handling and flexibility over conventional systems. In brief, the most interesting features of this system which will be discussed are
simplified system operation and control,
full precision instantaneous floating point capability, and
quality control.
Having a minicomputer integrated into the acquisition system allows simplified set-up and operation of the entire system. Communication with the system by the operator is accomplished exclusively through the keyboard and display of a CRT terminal. The display terminal is used in either of two modes by the operator, monitor or interactive. As a monitor, the system can provide an immediate display of operational parameters or system conditions. As an interactive device, the system can guide the operator through desired changes in operating parameters within limits set by the system.
The full floating point amplification and the ability of the system to deal with this form of data with full precision is of course important. There are several significant advantages offered by instantaneous floating point data. A system using this data will not Boon become obsolete. The technique gives a wide dynamic range (174 db in this case). Large changes in amplitude can occur without amplifier distortion. Also, small signal resolution is improved. Measuring accuracy is constant due to the A/D converter being operated within a restricted range of voltage input. The floating point technique also requires no manual control or settings.
Quality control is easily applied with this type of system. There are several ways quality of data is insured. One way is by making available results of instrument tests quickly and in hard copy form. Also, continuous quality control of data as it is acquired is applied before it is recorded. Data quality is further improved due to the wide range of data processing that can be performed by the system which was previously done only at distant processing centers.
