Generate Sweep signal
This module generate multiple repetitions of the Sine Sweep signal (also known as Stretched Pulse, and not very dissimilar from TDS - Time Delay Spectrometry). In practice, it is a sinusoidal signal, which frequency is continously varied (not in steps) from a starting frequency up to an end frequency, covering the frequency range of interest. It is possible to produce multiple repetitions of the test signal, with an optional silence gap between them:
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If a stereo waveform is generated, the selected number of repetitions is placed first on the left channel, thereafter on the right channel. In this case, anyway, a single repetition (cycle) of mono signal is produced, with exponential frequency variation ("pink", or log, spectrum):
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As it is shown, a proper fade-in and fade-out at the extremes of the signal are automatically performed.
During the generation of the excitation signal, a proper inverse filter for the deconvolution of the impulse response is preloaded onto the Windows clipboard:
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In order to recover the impulse response, the recording made after the excitation of the system with the sweep signal must simply be convolved with the inverse filter. This is demonstrated by the fact that, convolving the above signal with its inverse filter, an almost perfect Dirac's delta function is obtained:
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