METHOD AND APPARATUS FOR THE DETERMINATION OF START TIME DIFFERENCE AND OVERALL PHASE SHIFT BETWEEN TWO SIGNALS

摘要

The time displacement tau and total phase difference phi 0 between two sliding-frequency signals, needed for checking vibrators in the seismic exploration method, are obtained in that for a number of frequencies f contained in these signals, a value phi (f) specifying the phase relationship, for example the arctan of the quotient of the real part and the imaginary part of the product of the Fourier transform of one signal and the conjugate-complex of the Fourier transform of the other signal, are determined and a straight line g(f) = Af + B, which deviates least from phi (f), is established. The slope of the straight line A provides the time displacement tau = A/2 pi and the ordinate section B provides the total phase difference phi 0 IDENTICAL B modulo 2 pi . The relevant device contains, in addition to the signal generator (1), phase shifter network (2), controller (3), vibrator (4), comparison circuit (5) and vibrator baseplate (8) with receiver (6) and test accelerometer (7), also an analog/digital converter and multiplex device (15), a Fourier transformation unit (16), an arithmetic circuit (17) for determining phi (f) and a circuit (18) for determining A and B with indicating device (20). A circuit (24) with analog display (22) is used for determining the residual phase shift and a circuit (26) is used for determining a statistic measure for the residual phase shift. IMAGE