Abstract: In accordance with illustrative embodiments, methods and apparati, which determine jitter are described. In one example embodiment, a method includes receiving a signal, wherein the signal comprises a first data pattern which was generated at a first bit rate. The method also includes sampling the signal at a second bit rate to generate a second data pattern. The period of the second bit rate is different from the period of the first bit rate. The method also includes comparing the first data pattern and the second data pattern to determine differences between the first data pattern and the second data pattern. Furthermore, the method includes determining jitter in the signal according to the differences between the first data pattern and the data second data pattern. In other embodiments, by using two different bit rates to determine jitter, jitter can be determined in communication systems in a convenient and cost effective manner.

Abstract: A tester for testing components of a communication system, such as an optical communication system is disclosed. The tester may utilize a testing method to test a communication component (e.g. a cable or repeater) by stressing a test signal. The tester may utilize external transmitters and external receivers in order to implement the test in a similar communication environment as the tested communication components normally operate.