# Run time tolerance calculation

The **transit time** tolerance calculation deals with the calculation of signal **transit** times in networks with components (gates), the transit times of which can lie within a certain tolerance range. The minimum and maximum possible total runtimes through the network are of interest. The network must be coordinated so that both cases lead to the same result. Described clearly, slow components slow down the entire network because faster components may have to wait.

The methods of run-time tolerance calculation are used in various areas of electrical and digital technology .

## Series connection of two gates

When two gates are connected in series, the signal must first pass through the first component and then the second component. The signal transit times of the individual gates add up here.

Minimum running time through both gates:

*t*_{min}= t_{1, min}+ t_{2, min}

Maximum runtime through both gates:

*t*_{max}= t_{1, max}+ t_{2, max}

(With *t _{x, min / max}* : minimum / maximum runtime of gate x)

## Parallel connection of two gates

Assume that the input of both gates is on the same line. However, due to the difference in transit time between the gates, the signals arrive at the outputs with a time delay. The following formulas are used to calculate the minimum / maximum time difference between the two output signals:

*t*_{diff1}= t_{1, max}- t_{2, min}

*t*_{diff2}= t_{1, min}- t_{2, max}

(With *t _{x, min / max}* : minimum / maximum runtime of gate x)