|LEVEL 0| |HOMEPAGE|
GLOSSARY OF TERMS USED IN TIME SERIES ANALYSIS
OF CARDIOVASCULAR DATA
ANALYTIC SIGNAL

Signal with Fourier transform equal to 0 for frequencies lower than 0

This is a desirable property when the Wigner-Ville is computed. However, most practical signals (tachogram, systogram etc) are real, condition which implies a negative frequency component for each positive frequency component, and so they are not analytic signals. An analytic signal z(t) can be generated from a real signal s(t) suppressing the negative frequency components while preserving the positive components as:

z(t) = s(t) + i H[s(t)]
where H[*] is the Hilbert transform operator, and i2 = -1.

References:
Reilly A., Frazer G., Boashash B. (1994) Analytic signal generation - Tips and traps IEEE Trans. on Signal Processing, 42, 3241-3245

Links:
Source Code for generating an analytic signal through the computation of the Hilbert Transform  from the  Space and Atmospheric Research site of the University of Western Ontario

 (PC 19/02/2000)
|LEVEL 0| |HOMEPAGE|