A transponder unit for the contactless transmission of modulated data to a reader is provided. The transponder unit includes a clock generator configured to generate a clock signal and to synchronize the clock signal in a synchronization mode, on the basis of a signal received from the reader, and a modulator, the modulator configured to modulate data on the basis of the clock signal from the clock generator. The modulator is configured to generate a modulation pause by masking out at least one modulation component, the modulation component being smaller than a modulation pulse. The modulator is further configured to send the signal for starting the synchronization mode to the clock generator during this modulation pause.