hi,damian,i want to calculate the total jitter including Deterministic and random jitter in the system.i do not think the main problem in my simulation is the lack of jitter because the problem also exist when i use the example MEASURE JITTER ,which add jitter and noise source.May be It is the main noise source in my simulation when i use a 100km undirectional fiber.when i use a ultra-long bidirectional fiber like 1000km and bidirectional EDFA,may be they are the main noise source.thank you for your response!