Timing noise, glitches and the braking index of PSR B0540-69

We report a pulse-time history of PSR B0540-69 based on the analysis of an extended data set including ASCA, BeppoSAX and RXTE observations spanning a time interval of about 8 years. This interval includes also the epoch of the glitch episode reported by Zhang et al. (\cite{Zha01}). Our analysis shows the presence of relevant timing noise and does not give clear evidence of the glitch occurrence. We performed an accurate evaluation of the main timing parameters, nu , dot í and ddot í and derived a mean braking index of n=2.125+/-0.001 quite different from the lower value found by Zhang et al. (\cite{Zha01}), but in rather good agreement with several other values reported in the literature. Table A1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/402/647