Controlled amount of jitter injection into high speed serial bit stream is required for SerDes jitter tolerance test. While jitter injection by Direct Time Synthesis can be a much more cost effective method than a combination of several instruments, it is not widely used yet. Considering its high potential in high volume production test cost reduction, we have studied the basics of the jitter injection flexibility and accuracy of our test system, and the high end ATE seems to be acceptably accurate for high volume production test of multi-gigabit SerDes. The results of our studies provide a foundation for further exploitation of jitter injection using Direct Time Synthesis method.