Due to the clocked mode of operation, electromagnetic interference signals originate from digital hearing aid device or hearing device systems with the clock frequency and its harmonics. These can disrupt the wireless signal transmission between the hearing aid device or hearing device system and a further device. To prevent these disruptions, the invention provides a jitter unit that is connected with the clock generator and causes frequency oscillations in the clock signal. The interference signals caused by the clock signal are thereby lowered with respect to their amplitudes, whereby an interference-free signal transmission is enabled between a transmitting and/or receiving unit connected with a hearing aid device and an external device.