| 摘要 |
<p>In cableless seismic recording, each seismic trace is digitally recorded by a separate small portable magnetic recorder placed near the corresponding seismometer group. First, out of a large number of seismometer groups and small recorders spaced over an area or along a profile line, only the specific recorders needed for a given set of record traces are turned on from a control point, typically at the seismic source location, by transmitting a set of coded signals over a communications link. Next, a record header block of identification and recording parameter data, partly transmitted from the control point and partly supplied by the portable unit, is recorded on the tape by transfer from temporary storage in the unit. Finally, immediately following the end of the header, are recorded the zero-time mark and the timed sequence of digitized seismic trace data. For the next and each following record, the process is repeated except that the coded signal set is modified as necessary to turn on only the appropriate trace recorders.</p> |
