can some one tell me how the sweep profiles the phase of each frequency, and how this is reflected on the impulse sweep...I can see that when the sweep moves across the spectrum to profile a systems physical properties it modulates in amplitude and pans left and right but how about the phase, how can we observe the phase effect on the sweep...

1 Answer 1


The phase characteristic of a sweep signal is linear, starting from 0 and increasing over time up to 2*Pi.

For a very clear explanation of this, I suggest you see the paper Transfer-Function Measurement with Sweeps from Swen Müller and Paulo Massarani.

If you use a sweep signal to measure an impulse response, the phase curve will have to be compared to this linear curve to understand the time delays (phase shifts) introduced at each frequency.

  • measuring the phase offsets/fluctuations is where I am having difficulty with, simply put what kind of audio manipulation to the sweep introduces these phase offsets at different frequencies...is there a matlab code to plot the phase offsets introduced by the impulse being profiled with the sweep, or some kind of phase meter that is on phase to frequency mode, to observe the phase shifts at different frequencies while processing the sweep, simple pitching up and down the sweep at different frequencies of the sweep, will that introduce phase offsets to our impulse when the sweep is deconvolved?
    – texture
    Apr 22, 2015 at 10:14
  • JimiJazz, by the way thanks for that in depth scientific article...very informative data.
    – texture
    Apr 22, 2015 at 10:16
  • I found this tool to measure and display the phase to frequency of the sweep once it is deconvolved into an impulse...Christian/Applications/Measurement/VSTPluginAnalyser
    – texture
    Apr 22, 2015 at 23:25
  • @texture if you're still interested in Matlab code to watch the effects I would try the ITA Toolbox, and would then subtract the phase response of your system to the phase response of the sweep.
    – jimijazz
    Apr 23, 2015 at 17:31
  • thanks JimiJazz, that was very helpful! those tools are awsome and well coded.
    – texture
    Apr 23, 2015 at 17:41

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