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This example shows how to account for the frequency response of detectors when this response has a Gaussian shape (e.g., piezoelectric transducers). It builds on the Homogeneous Propagation Medium Example.
The frequency response of the sensor is assigned using the frequency_response
field of the sensor
input structure. This accepts two parameters, one for the center frequency, and one for the bandwidth of the frequency response. The transducer bandwidth, defined as a percentage, controls the FWHM of the filter, where the FWHM = % bandwidth * center frequency.
% define the frequency response of the sensor elements center_freq = 3e6; % [Hz] bandwidth = 80; % [%] sensor.frequency_response = [center_freq, bandwidth];
When an input for sensor.frequency_response
is supplied, a Gaussian filter is applied within the simulation functions after the simulation is completed by multiplying the Fourier transformed signals by a zero-phase Gaussian window.
To illustrate the effect of the filter, the time series recorded at the first sensor position for a simulation with and without the sensor.frequency_response
field defined are plotted below. The corresponding amplitude spectrums are also shown. The removal of the low frequency information has a significant effect on the signal amplitude.
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Recording The Particle Velocity | Comparison Of Modelling Functions | ![]() |
© 2009, 2010, 2011 Bradley Treeby and Ben Cox.