Zerocrossingtiedot

Zerocrossingtiedot, or zero-crossing data, refer to information about the moments when a signal crosses zero amplitude. In practice, such data typically include the time stamps of zero crossings, the direction of crossing (negative-to-positive or positive-to-negative), and, if available, a refined estimate of the exact crossing time obtained by interpolation between adjacent samples. Zerocrossingtiedot can be derived from various signals, including audio, electrical waveforms, and other oscillatory data.

They are computed from sampled signals by detecting sign changes between consecutive samples. The crossing time can be estimated with linear interpolation between the pair of samples that straddle zero. Some datasets also record the amplitude near the crossing or the slope of the signal at the crossing.

Applications include pitch and tempo estimation in audio processing, onset detection in music, speech processing, and timing recovery in digital communications or synchronization in power systems.

Limitations include sensitivity to noise, which can produce false crossings; the need for sufficient sampling rate and preprocessing; and the fact that zero-crossing data discard much of the waveform detail, making it less robust to amplitude modulation.

Related concepts include the zero-crossing rate (ZCR), which summarizes the number of crossings in a time window, and other spectral or time-domain features used for robust signal analysis.