Karinathan
Mechanical
Can anybody explain the concept of MLS to me? Why this signal has the flat frequency spectrum? Also, How can I calculate the power from this signal?
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Maximum Length Sequence (MLS)
- Thread starter Karinathan
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Here are some good links to start from.
Else tray Google they can give you 10.000 of hits
Else tray Google they can give you 10.000 of hits
A maximal sequence has a flat spectrum like white noise. The output of such a sequence (typically +/1 values that look random) is sometimes called pseudonoise because it looks like it was generated by a pure random process. The spectrum is flat if you take the fourier transfrom of the autocorrelation of the sequence with itself.
a memoryless random process will correlate with itself only when the sequence is time aligned with itself--any shift of one sample or more will result in a zero correlation if the sample is large. Max. Len. linear. shift registers will produce a sequence that appears random statistically but in fact is not.
a memoryless random process will correlate with itself only when the sequence is time aligned with itself--any shift of one sample or more will result in a zero correlation if the sample is large. Max. Len. linear. shift registers will produce a sequence that appears random statistically but in fact is not.
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Karinathan
Mechanical
I see... Thank you for BDJ's website and Johnwiss.. Actually I have tried to find the info. from the website before but I couldn't get the information that I want.. (or maybe I'm not clever enough to understand their 'mathematical explanation')
What I want to find out is that, normally the MLS will use the correlation to get the linear transfer function of the system.. but I use MLS to feed the loudspeaker and use FFT to get its frequency response without using the correlation because I think that if MLS has the flat frequency spectrum then I should be able to use it as white noise. Isn't it right?
The results I got from this method (FFT) can be comparable to the result from the white noise...(I mean the FFT shape) but what I stuck is how can I get the MLS's power from the signal I generate as I want to get the sensitivity of the loudspeaker in the same time.. (i.e. the dB/1 meter/1 Watt)
Umm... as I read from some papers... so far I haven't seen anybody mentioned about this issure.
What I want to find out is that, normally the MLS will use the correlation to get the linear transfer function of the system.. but I use MLS to feed the loudspeaker and use FFT to get its frequency response without using the correlation because I think that if MLS has the flat frequency spectrum then I should be able to use it as white noise. Isn't it right?
The results I got from this method (FFT) can be comparable to the result from the white noise...(I mean the FFT shape) but what I stuck is how can I get the MLS's power from the signal I generate as I want to get the sensitivity of the loudspeaker in the same time.. (i.e. the dB/1 meter/1 Watt)
Umm... as I read from some papers... so far I haven't seen anybody mentioned about this issure.
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