DocumentCode :
894452
Title :
On amplitude and frequency demodulation using energy operators
Author :
Maragos, Petros ; Kaiser, James F. ; Quatieri, Thomas F.
Author_Institution :
Div. of Appl. Sci., Harvard Univ., Cambridge, MA, USA
Volume :
41
Issue :
4
fYear :
1993
fDate :
4/1/1993 12:00:00 AM
Firstpage :
1532
Lastpage :
1550
Abstract :
It is shown that the nonlinear energy-tracking signal operator Ψ(x)=(dx/dt)2-xd 2x/dt2 and its discrete-time counterpart can estimate the AM and FM modulating signals. Specifically, Ψ can approximately estimate the amplitude envelope of AM signals and the instantaneous frequency of FM signals. Bounds are derived for the approximation errors, which are negligible under general realistic conditions. These results, coupled with the simplicity of Ψ, establish the usefulness of the energy operator for AM and FM signal demodulation. These ideas are then extended to a more general class of signals that are sine waves with a time-varying amplitude and frequency and thus contain both an AM and an FM component; for such signals it is shown that Ψ can approximately track the product of their amplitude envelope and their instantaneous frequency. The theoretical analysis is done for both continuous- and discrete-time signals
Keywords :
amplitude modulation; demodulation; frequency modulation; signal processing; AM signals; FM signals; amplitude demodulation; amplitude envelope; approximation errors; continuous time signals; discrete-time signals; energy operators; frequency demodulation; instantaneous frequency; nonlinear energy-tracking signal operator; signal processing; sine waves; Demodulation; Frequency modulation; Intelligent control; Laboratories; Oscillators; Signal analysis; Signal generators; Speech analysis; Speech processing; Underwater vehicles;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/78.212729
Filename :
212729
Link To Document :
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