Superconducting accelerating cavities can be operated in the pulse mod
e to lower capital and operating costs of the cryogenic plant. Some ad
ditional cost reduction is also possible when the accelerating process
takes place already during the fill time, i.e. before the acceleratin
g structures reach the final steady state. Such an operation needs mor
e analysis of the transient state in multicell cavities. In this paper
one possible approach to the complete analysis of the transient state
in standing wave accelerating structures is presented. The different
approach, giving envelope of the transient state, the reader can find
in.(1) In this paper set of equations derived from a lumped element re
placement circuit model used for the analysis, is solved in a semi-ana
lytic way. The method of solution is based on the classical Laplace tr
ansformation aided by some additional numerical calculations. The comp
uted cavity response to the harmonic driving source agrees well with m
easurements for various types of cavities. As an example, comparison o
f the transient state measurements and calculations for a 9-cell, 1GHz
copper cavity are discussed in more detail. Next, diagrams relating c
avity parameters to the time delay al the beginning of the fill and to
the phase deviation for the steady state, computed with a program wri
tten especially for this analysis are given. Finally, some preliminary
computations for structure of the future superconducting linear colli
der TESLA are discussed.