After understanding how to select a clock tree component based on jitter, next the engineer needs to know how to estimate the total clock tree jitter, end-to-end. The total clock tree jitter should be estimated to determine if there is sufficient system-level design margin before the clock tree is committed. A component with poor performance can compromise the whole system. Thus, understanding jitter specification of each component is an important basis. With this information the engineer can estimate the entire clock tree’s jitter. Two critical points to note: total jitter is not the sum of the MAX RMS specifications of each component and total jitter is the root of the sum of squares of each device's MAX RMS jitter, as shown in the formula here.