20.01.2015 Views

njit-etd2003-081 - New Jersey Institute of Technology

njit-etd2003-081 - New Jersey Institute of Technology

njit-etd2003-081 - New Jersey Institute of Technology

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

47<br />

3.2 The Uncertainty Principle<br />

The uncertainty principle in time-frequency analysis provides the lower limit on the<br />

spread <strong>of</strong> signal energy in time and frequency. To define the spread <strong>of</strong> a signal in time<br />

and frequency, one first need to define the average time and average frequency <strong>of</strong> a<br />

signal [38]:<br />

defined as:<br />

The spread <strong>of</strong> the signal in time (duration) and frequency (bandwidth) are<br />

The uncertainty principle states that:<br />

Therefore a signal cannot have an arbitrarily small duration and bandwidth. A<br />

Gaussian signal:<br />

meets this bound with equality where a is an arbitrary constant.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!