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timeShift

Shift time series to and from staggered temporal grid

Syntax

data = timeShift(data, dt)
data = timeShift(data, dt, true)
data = timeShift(data, dt, false)

Description

timeShift shifts an input time series (or 2D array of time series) to and from a staggered temporal grid using Fourier interpolation. If the input data is defined as a 2D array of time series, the temporal shift is performed along the second dimension assuming that the array is indexed as (n, t). This function can be used to shift the acoustic particle velocity recorded by the first-order simulation functions to the regular (non-staggered) temporal grid. An example of shifting a discretely sampled cosine is given below.

dt      = pi/5;
t       = 0:dt:(2*pi - dt);
y       = cos(t);
y_shift = timeShift(y, dt);
y_ref   = cos(t + dt/2);
plot(t, y, 'k-s', t, y_shift, 'b-s', t, y_ref, 'rx');
legend('Original Function', 'Shifted Function', 'Reference');

Inputs

data

1D or 2D input data, for 2D input data, the time shift is performed along the second dimension

dt

time step [s]

Optional Inputs

forward

Boolean controlling whether the time series is shifted forward or backward in time (default = true)

Outputs

data

shifted time series

See Also

gradientSpect, kspaceFirstOrder1D, kspaceFirstOrder2D, kspaceFirstOrder3D, pstdElastic2D, pstdElastic3D


© 2009-2014 Bradley Treeby and Ben Cox.