# TI (1E-XX)

TI (p-p), Total Interference, is the width of the one (or zero) level distribution at a low probability or symbol error rate (SER). TI is always measured at the same SER as the Eye Height measurement. By default this is a SER of 1E-12 (1 x 10–12), which is a probability of occurrence of less than 1 part per trillion. You can change the SER setting to any value between 1E-6 to 1E-18 by changing the Probability/SER Level settings in the Advanced Tab.

The TI measurement is derived from the Deterministic Interference (DI) and Random Noise (RN) measurements. The DI and RN values are combined according to a dual Dirac model. This model is converted to a SER curve which is then evaluated at the desired SER to obtain the TI measurement.