ST. LOUIS--(BUSINESS WIRE)--Belden Inc. (NYSE: BDC), a global leader in high quality, end-to-end signal transmission solutions for mission-critical applications, today reported fiscal first quarter 2015 results for the period ended March 29, 2015. First Quarter 2015 Highlights Grew revenues by 12.2% year-over-year; Achieved record adjusted gross profit margins of 40.6%, increasing 450 basis points from 36.1% in the year-ago period; Expanded adjusted EBITDA margins to 15.5%, increasing 40 basis