Field deflection circuit in a picture display device

A circuit for field deflection in a picture display device, comprising a generator for generating an essentially sawtooth-shaped variation, a power amplifier coupled to the generator and a field deflection coil connected to an output of the amplifier, the sawtooth generator being provided with a storage element, first means for causing a change of a quantity of information stored in the storage element in one direction during a first part of a field period and second means for causing a change of said quantity in an opposite direction during a remaining second part of the field period so that the essentially sawtooth-shaped variation is produced, the sawtooth generator also comprising a control loop for controlling the quantity of information stored in the storage element for rendering a mean value of the change of said quantity during the second part of the field period equal to a mean value of the change of said quantity during the first mean part of the field period, characterized in that the control loop comprises an integrator for integrating the quantity of information stored in the storage element with an integration period which is not shorter than one picture period, and a comparison stage coupled to the integrator for comparing the output signal of said integrator with a reference value, the output of said comparison stage being coupled to the second means.