On-bottom seismometer electronic system
AssigneeMobil Oil Corporation
InventorsEdgar A. Bowden, Gordon R. Deline, Gerard D. Koeijmans
Life of this patent
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Abstract
An ocean bottom seismometer unit records refraction waves from a seismic source. The refraction waves are digitzed and stored in a magnetic memory. Periodically, a tape recorder is started and digital samples are transferred from digital memory to tape during a time in which operation of the tape recorder will not generate spurious noise signals which interferes with the detection of the refraction waves. The water break is detected and the time of its occurrence is digitized. Only the digitized time of the water break occurrence is recorded thereby permitting shortened record length and increased record storage capacity.
Claims14
An ocean bottom seismometer unit for recording waves traveling from a source of seismic pulses comprising:
- a hydrophone producing signals representing water break waves arriving at said hydrophone through the water from said source;
- a water break detector responsive to said hydrophone signals producing a water break signal representing the arrival of said water break waves at said hydrophone;
- means for digitizing the time of occurrence of said water break waves at said hydrophone;
- means for digitizing the time of occurrence of said water break signal;
- a digital memory;
- means for storing a plurality of said digitized water break signal times in said digital memory before recording them on said magnetic tape recorder unit whereby an array of digitized water break signal times are stored in said memory after each seismic pulse;
- a magnetic tape recorder unit and;
- timing and control means for starting said magnetic tape recorder unit and ransferring said digitized water break signal times from said digital memory to said recorder unit for recording after the occurrence of a seismic pulse and stopping said magnetic tape recorder unit after the recording of said digitized water break signal times and before the occurrence of the next seismic pulse.
An ocean bottom seismometer unit for recording waves traveling from a source of repetitive seismic pulses comprising:
- means for detecting a water break time and producing an output signal in response thereto;
- an analog to digital converter connected to the output of said means for detecting and converting said output signal to digital samples in a refraction record;
- means for recording said record;
- and
- timing and control means for disabling said means for recording at predetermined intervals including a clock circuit producing clock pulses, a digital counter responsive to said clock pulses and a digital register containing a digital representation of a time period after which a task controlled by the timing and control means must be repeated, the contents of said register being periodically transferred to said digital counter and said clock pulses being applied to said digital counter so that it periodically outputs a signal to control the performance of said task.
Dependencies are inferred from the claim text.