System information

Blastware Advanced Module
____________________________________________________
6–30 Blastware Operator Manual
• Hanning Window – This is one of the more popular Window functions. The Hanning
window has a shape similar to that of a cosine wave, and along with general analysis
purposes, it is useful for analyzing transients that extend past the time duration of the
window.
• Hamming Window – The Hamming window is a modified function of the Hanning
window; it also has the shape similar to a cosine wave. Within the time domain, the
Hamming window does not get as close to zero near the edges as does the Hanning
window, and though it provides an excellent spectral peak, the reduction in spectral
leakage is nominal.
• Blackman Window – The Blackman window has a weighting function similar to the
Hanning and Hamming window functions and has a narrower shape, still reflecting that
of a cosine wave. The spectral peak sharpness is only fair, but it is ideal for reducing
spectral leakage.
• Triangular and Bartlett Window – The Triangular and Bartlett windows offer an
identical triangular shaped weighting function (both names are included as either/or are
used in the industry), which will bring the signal to zero at the edges of the window. This
window produces a sharp spectral peak while concurrently reducing spectral leakage.
• Welch Window – The result of the Welch window function is a parabolic curve. The
Welch window is used to smoothly bring the signal down to zero at the edges of the
sampled region. Due to the averaging of the function it substantially decreases the low
frequency resolution.
e. Filter
Frequencies may be filtered out or removed from waveforms using the filter command. Review
the image below for the area that each of the filters effects:
Hanning