Patent ID: 6366536
Filing Date: 2002-04-02
Classification: B06B,G01V

Abstract:
A device for seismic acquisition in a marine environment, of the type comprising:a low-frequency transducer (12) with wide frequency band of the Janus-Helmholtz type, intended for emitting electromagnetic waves towards the sea bed, and a receiver (18) formed of a plurality of hydrophones for capturing the seismic waves reflected by the various layers of the sea bed, characterized in that the transducer (12) is driven by a computer (13) which records the data and programs the signal and the shape of the acoustic waves to be emitted and by a linear power amplifier of class A B or of class D, which delivers a power of between 3 and 9 KVA and in that an impedance matcher (16) is mounted between the transducer and the amplifier so as to allow wide band and high power matching to the transducer, said impedance matcher comprising a compensation inductor serving to correct the impedance of the transducer by lowering its capacitance, a transformer which matches the corrected impedance of the transducer to the output impedance of the power amplifier and a quenching resistor which makes it possible to reduce the excitation power and to smooth the response of the transducer, the transducer thus driven emitting a signal extending over a frequency band lying between a few hundred Hz and 10,000 Hz approximately with an emission level of around 200 dB over a frequency range lying between 600 and 2000 Hz.