An integrated circuit for analyzing the waveform of an input signal includes a first storage circuit and a second storage circuit that are each supplied with the input signal. The first and second storage circuits are controlled by a clock signal. The first storage circuit is used to store a state for the input signal when the clock signal has a rising edge. The second storage circuit is used to store a state for the input signal when the clock signal has a falling edge. An evaluation circuit compares the states of the input signal that are stored in the first and second storage circuits during a selected time span. The comparison can be used to decide whether the input signal assumes periodic fluctuations or an approximately permanently static value during the time span.