CHELMSFORD, Mass., March 23, 2016 -- Mercury Systems, Inc. , today announced that it has signed a definitive agreement with Microsemi Corporation to acquire the embedded security, RF and Microwave, and custom microelectronics businesses of Microsemi. For the twelve months ended September 27, 2015, these businesses had combined revenues of approximately $100 million and pro forma standalone adjusted EBITDA of approximately $28 million.