EMI immunity evaluation of an electro optical (laser) receiver

An electro optical receiver intended for combat tank application, developed by IRDE, Deradhun, was subjected to a series of EMI/EMC evaluations at the test centre of CVRDE. This system briefly consists of a number of laser detector heads, a processing electronics box and a display unit. In the initial phase of the testing, the system failed in the immunity tests and also exhibited false triggering frequently. The whole layout was analysed reengineered and evaluated again as a subsystem independently and there after integration in the vehicle also. Details of EMI-EMC tests carried out, observations made and EMC design guidelines furnished to the subvendor are discussed briefly in this paper. After thorough reevalutions to validate the EMI hardening, the system was found acceptable and the EMC performance had improved much better. Salient features of the system and its EMI characteristics are presented.