The tables below represent the components of Teradyne’s convertible senior notes:


	March 31, 2013		December 31, 2012
	(in thousands)
Debt principal	$	189,998	$	190,000
Unamortized debt discount		16,350		20,104

Net carrying amount of the convertible debt	$	173,648	$	169,896


	For the Three Months Ended
	March 31, 2013		April 1, 2012
	(in thousands)
Contractual interest expense	$	2,137	$	2,161
Amortization of the discount component and debt issue fees		3,957		3,479

Total interest expense on the convertible debt	$	6,094	$	5,640