# Noise Bathtub

The Noise Bathtub graph shows zero level data on the left side and one level data on the right side. The SER Bathtub graph plots TI (Total Interference) data and dual-Dirac SER values across the entire amplitude range on the horizontal axis.

The dual-Dirac SER values are calculated using DI(δ-δ) (Deterministic Interference) and RI (Random Interference) and are used to extrapolate to low SER levels. In general, the dual-Dirac values will differ from the measured TI values at high probabilities, but the two should converge at low probabilities.

The SER value used for calculating TI can be changed from its default value of 1E-12 in the Advanced Tab.