Development of the programmable TVG-TVF seismic profiler

Abstract

We have developed a microcomputer-based unique seismic profiler which has a function of programmable time-variant gain (TVG) and time-variant filtering (TVF). An aim of the system is to improve the quality of single-channel analog seismic profiler records. The system consists of a voltage controlled amplifier for the TVG, low-pass and high-pass voltage tuneable filters for the TVF, D/A converters which convert digital control data to voltage for TVG and TVF, a sea bottom detector, and microcomputers. An operator can freely set the condition of TVG and TVF by programming of the control data on the microcomputer, and the TVG amplifier and TVF filters are controlled according to the programmed data. TVG and TVF control starts from near sea bottom using the sea bottom detector or external digital depth data. The control data can be changed at any time during survey. We named the system PRO-SEA II (Programmable Seismic /Amplifier Two). A field test of the system was successfully carried out. Resolution and penetration depth of the seismic records were improved remarkably compared with conventional single-channel analog records.