Abstract: An oscillator unit for a base station or the like in a digital cellular radio network. The oscillator unit includes an adjustable oven stabilized crystal oscillator (21). The oscillator unit additionally includes a non-volatile memory (27), in which is stored a control information defining the frequency of the oven stabilized crystal oscillator (21) at the start of the oscillator unit, apparatus (30, 31, 32) for deriving a reference frequency from a fixed digital transmission connection, such as a PCM connection, between the base station and the remaining cellular radio network, a frequency control loop (21, 22, 23, 24) for maintaining a long-term stability for the oven stabilized crystal oscillator (21) on the basis of a long-term average of the difference between the frequency of the oven stabilized crystal oscillator and the reference frequency.

Abstract: A radio transceiver system is provided with transceivers for transmitting an outbound signal at least at one transmitting frequency and for receiving an inbound signal at least at one receiving frequency. Baseband signal processors are also provided for baseband processing of the outbound signal before conversion up to the transmitting frequency and of the received inbound signal after conversion down from the receiving frequency. To reduce cable laying in equipment racks and to simplify the realization of baseband frequency hopping, a bidirectional serial digital transmission channel is provided between transceivers and baseband signal processors, whereby both the inbound signal from a transceiver and the outbound signal applied to the transceiver are time-division multiplexed to said bidirectional serial digital transmission channel.