Accession Number : ADD009584

Title :   Chirp Filters/Signals.

Descriptive Note : Patent,


Personal Author(s) : Alsup,James M

Report Date : 11 May 1982

Pagination or Media Count : 6

Abstract : A discrete chirp generator produces discrete chirp signals which correspond to either of two exponential functions, namely the functions exp j pi(m2 + a)/N)) or exp (j pi(m(m + Beta)+a)/N), where m = 0, 1, 2, ..., M. Typically, M and N might both have the value 256. Similarly, a discrete chirp filter is described by its impulse repsonse which has one of these same two functional forms. These two new components (discrete chirp generator and discrete chirp filter) can be used to implement (a) an improved type of frequency synthesizer, and (b) an improved type of discrete Fourier transformer. In the former, a single generator is used in conjunction with delay, conjugation, multiplication, and low-pass filter components to achieve an improved synthesizer. In the latter, either of the two discrete chirp function generators is combined with an input signal gn in an multiplier. The output of the multiplier is fed into the input of a filter which is configured in a manner similar to the same chirp function as the chirp generator, except that the exponential has the opposite sign in the filter from the sign of the chirp function generator. The output of the filter is combined in a multiplier with a similar chirp function, to result in a complex output signal Gm which represents the discrete Fourier transform of the input signal gn. (Author)

Descriptors :   *Patents, *Chirp filters, *Signal processing, Signal generators, Discrete fourier transforms

Subject Categories : Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE