The classical delta filters used in the current resonant bar experiments fordetecting GW bursts are viable when the bandwidth of resonant bars is few Hz.In that case, the incoming GW burst is likely to be viewed as an impulsivesignal in a very narrow frequency window. After making improvements in theread-out with new transducers and high sensitivity dc-SQUID, theExplorer-Nautilus have improved the bandwidth ($\sim 20$ Hz) at the sensitivitylevel of $10^{-20}/\sqrt{Hz}$. Thus, it is necessary to reassess thisassumption of delta-like signals while building filters in the resonant bars asthe filtered output crucially depends on the shape of the waveform. This ispresented with an example of GW signals -- stellar quasi-normal modes, byestimating the loss in SNR and the error in the timing, when the GW signal isfiltered with the delta filter as compared to the optimal filter.
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