WIENER FILTERS FOR GRAVITATIONAL-WAVE ANTENNAS - CHARACTERISTICS AND APPLICATIONS

We report on the application of Wiener filters to the data of Weber-ty pe gravitational-wave antennas, with particular reference to data proc essed by means of lock-in amplifiers driven at the frequencies of the modes of the detector. After a review of some basic results concerning the filtering of the data, we briefly examine the relationship betwee n Wiener filters and matched filters. The discussion that follows is c entred on various aspects related to the practical application of Wien er filters as well as on their limitations, also addressing the depend ence of their performance on the values of their parameters. Finally, we consider some applications of non-optimal Wiener filters: by reduci ng the filter smoothing time constant, the time resolution can be incr eased; by increasing it, the filter becomes an estimator of the Browni an motion.