A phase-locked loop is described and has a phase detector that provides at its
output per clock cycle a current pulse whose pulse duration is a measure of a phase
difference between an input signal and an output signal of the phase-locked loop.
A loop filter is connected downstream of the phase detector. The loop filter has
a converter device, at least one controllable switching device and at least two
switchable capacitive elements for storing a current pulse. In which case the converter
device, the switching device and the capacitive elements can be connected up in
such a way that the converter device provides a proportional current from a current
pulse coupled into at least one of the capacitive elements. An amplitude of the
proportional current is constant over the entire length of a clock period. An oscillator
is connected downstream of the loop filter, into which oscillator the proportional
current can be coupled.