| 摘要 |
Vibrator comprising a single vibration generator coupled with the medium by a coupling element and means for controlling the generator, suited to apply thereto, on each emission, a single pilot signal obtained by combination of at least two signals of different frequencies (f1, f2), fixed or preferably variable within at least partly separate frequency bands, and non-linear elastic transmission means suited to generate in the medium vibrations at a frequency depending on the frequency difference of the two vibrational signals. The exploration method comprises using the vibrator in order to emit very low-frequency vibrations in the medium reception by pickups (R) of the waves reflected by the medium in response to the vibrations emitted and recording thereof, and selection by correlation of the vibrational signals with a synthetic signal whose frequency is connected with the frequency difference of the signals forming the pilot signal.
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