APPARATUS FOR PHASE ANGLE DEMODULATION

摘要

An apparatus for phase angle demodulation. The apparatus functions as a highly-linear angle-modulation demodulator and is particularly useful for seismic streamers comprising very large arrays of optical hydrophones. The apparatus includes a demodulator (1) and a processor (2) in which the demodulator (1) contains a signal input (3) and a reference input (4). The apparatus is configured such that a phase modulated signal (6) having a carrier frequency (7) is connected to the signal input (3), and a reference signal (8) is connected to the reference input (4). A difference frequency is defined as the non-zero difference in frequency between the reference signal frequency (9) and the carrier frequency (7). The processor (2) filters the output signal (10) from the demodulator output (5) in order to provide an output (13).