Software for equalizing ultrasound signals

The ultrasound signals generated by medical ultrasound equipment must be characterized before such a device can be placed on the market. For this purpose, it would be ideal if the hydrophones used for these measurements had a large bandwidth and a sensitivity that is, as far as possible, independent of the frequency, so that an ultrasound device’s signals can be recorded without distortion. Real hydrophones, however, usually exhibit a clear frequency response, which leads to an unequal weighting of the spectral components measured. This means that the same sound pressure leads to different signal amplitudes at different frequencies. The frequency response of a hydrophone is determined by individual calibration. It is available to users in the form of a data set.

The signal deconvolution method allows such data to be compensated for the distortion arising during a measurement. In this way, the original ultrasound pressure signal can be reconstructed in a frequency range of up to 100 MHz. This method is based on the transfer function of the hydrophone considered (in the form of calibration data) and on the ultrasound signal measured by said hydrophone (in the form of a voltage signal). The final result of the reconstruction can be stated with its associated uncertainty.

The software program developed for this purpose can be used to assess your own measurements and can also be modified after it has been downloaded. If you access it online, it also provides an interactive tutorial explaining how to use the signal deconvolution method based on examples of measurement data. The focus lies on issues arising in ultrasound measurements, for instance, with examples of calibration data from different hydrophones and real measurement data of typical sound emission measurements using these hydrophones. But a transfer to signal deconvolution issues outside ultrasound exposimetry is also possible.

In addition, this software program forms the basis for standardization and will be referenced in the revised IEC 62127-1 Ed. 2 standard.