Abstract: In a frequency-modulated frequency generator comprising an oscillator connected in a phase control loop, the reference frequency is generated in a digital frequency synthesizer which is adapted to be frequency-modulated by digital data signals; under control of the data signal, numerical values are alternately read out from a register to result in corresponding different frequency deviations; the register stores further predetermined additional numerical values which result in frequencies adjacent to said frequency deviations; the register is controlled by the data signal so that for every edge of the data signal predetermined additional numerical values are initially read out in such an order that the frequency values produced thereby will compensate for any overshooting which occurs upon switching between the drift frequencies.