Accession Number : ADA320829

Title :   Identification of Push To Talk Transmitters Using Wavelets and Spectral Correlation.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Abdulla, Abdulla M.

PDF Url : ADA320829

Report Date : SEP 1996

Pagination or Media Count : 57

Abstract : The purpose of this thesis is to find an automated way to identify push-to-talk transmitters using a wavelet or a spectral correlation based approach. In the wavelet approach, a distance algorithm is applied to the wavelet scales of the signal and the template. One signal from each transmitter set is taken as a template. The distance algorithm computes the distance between the local extrema of the wavelet coefficients of the template and the signal. Results show that the Wavelet Transform (WT) distance algorithm is able to classify the four signal sets accurately. Good identification results are achieved even at low signal-to-nose ratios. In the spectral correlation approach an averaged template for each signal is used. The spectral coefficients for templates and signals are computed by extracting the magnitude squared of the Fast Fourier Transform (FFT) of the data. This method performs better for most signals better than the wavelet method because it can identify at lower signal to noise levels than the wavelet method does.

Descriptors :   *RADIO TRANSMITTERS, *WAVELET TRANSFORMS, ALGORITHMS, THESES, CORRELATION, FAST FOURIER TRANSFORMS.

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE