received in more than one sector since there is only one emitter source only one pulse will be selected after the arbitration is complete the a d converter 102 converts pulse amplitude information to a digital signal which represents the instantaneous amplitude present in the channel this instantaneous amplitude is sampled on a periodic basis such as every 20 nanoseconds or every 50 nanoseconds the digital processing of these signals allows simultaneous digital arbitration which eliminates a great number of spurious signals and insures that reported pulse descriptor words will contain important information about real signals that have been received after the arbitration is complete the digital information representing the received pulse is transferred to the parameter measurement block 110 this block determines the toa pa and tod of a particular signal this determination is made in real time which allows accurate and consistent representation of those parameters there are 96 of the parameter measurement modules 110 parameter calculations such as aoa f pw and pri are made in parameter calculator 112 in addition each parameter calculator can perform an environment filter function the environment filter screens output pdw 39 s for signals of interest and rejects signals not of.