280:. When generating a single frequency test signal for FFT analysis, it is possible to create the frequency such that it aligns perfectly within an FFT bin-centre frequency. These frequencies are multiples of the frequency resolution of the FFT, given by the sample rate divided by the number of sample points. This results in no spectral leakage and all the power from the signal is present in only one FFT bin. Viewed in the time domain, a sine wave will fit in the centre of an FFT bin if it has a complete number of cycles within the length of the sample buffer. Such signals can be analysed without an FFT window function provided the system is
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A bin-centres signal can give a frequency response with thousands of frequency points from a single capture of an FFT buffer and requires no averaging. Creation of stimuli that have specific spectral characteristics is also possible.
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The usage of bin-centre analysis techniques is mathematically inherent in FFT spectral analysis. Where it has changed has been with the introduction of digital
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has been used to reduce the effects of discontinuities at the ends of the FFT buffer, but these result in
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in order to get a clear idea of a trend. In addition, creation of
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bin-centre frequencies. This allows analysis without an FFT
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Rapid Audio
Frequency Response Measurement using Bin-centres
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noise signals in the time domain presents many challenges.
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signal which is inherently random requires considerable
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