Waveform Windowing
A test sequence demonstrates how SoundCheck’s Windowing post-processing function is applied to waveforms to remove measurement artifacts that might otherwise create false auto delay values and subsequent analysis errors
The purpose of this sequence is to demonstrate how SoundCheck’s Windowing post-processing function can be applied to waveforms to remove measurement artifacts that might otherwise create false auto delay values and subsequent analysis errors.
The data used in this demo sequence came from a customer who was measuring the directivity of a hearing aid-type device by mounting the DUT on a HATS and rotating it on a turntable while using a short duration (12ms) log sweep. The DUT does not have a perfect seal in the HATS ear and has signal processing which produces a latency of around 35ms. When viewing the Recorded Time waveforms, we can see the leakage signal at approx. 2.5ms and the amplified signal at approx. 38ms. As the DUT approaches 180° the magnitude of the leakage into the HATS ear exceeds that of the amplified signal which creates false Record Delay values and subsequent analysis errors. By applying a window to the Recorded Time Waveform, we can remove the early-arrival leakage, calculate the true Record Delay values of the amplified signal, and get consistent analysis results at all angles of rotation.
There are plenty of other ways in which this sequence could be adjusted to your specific requirements, for example adapting the windowing function to remove early arrival signals from a waveform, or editing out excessive delay in a waveform.
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