An intermodulation detection sub-system (103; 103'; 103"), comprising: a test signal generation module (304; 604) integrated into a unit of a telecommunications system, wherein the test signal generation module (304; 604) is configured to provide a test signal to a remote antenna unit (208a;...; 208f) of the telecommunications system, wherein the test signal generation module (304; 604) comprises: a first signal source configured to generate a first signal component; a second signal source configured to generate a second signal component; a combiner configured to generate the test signal by combining the first signal component and the second signal component; wherein the intermodulation detection sub-system (103; 103'; 103") further comprises at least one intermodulation detection device integrated into the telecommunications system, wherein the at least one intermodulation detection device is configured to detect intermodulation products generated by mixing the first signal component and the second signal component of the test signal, wherein the at least one intermodulation detection device is integrated into at least one of the remote antenna unit (208a;...; 208f) or the unit of the telecommunications system; and a controller integrated into the unit of the telecommunications system, wherein the controller is configured to control the test signal generation module (304; 604) and the at least one intermodulation detection device and wherein the controller is further configured to select a first frequency of the first signal component and a second frequency of the second signal component such that the sum or difference of the first frequency and the second frequency is a third frequency in an uplink frequency band, the intermodulation detection sub-system being characterized by a frequency scanner configured to detect an extraneous signal in a coverage area of the remote antenna unit (208a;...; 208f), wherein the controller is configured to select the first frequency and the second frequency such that the third frequency is different from a frequency of the extraneous signal. a test signal generation module (304; 604) integrated into a unit of a telecommunications system, wherein the test signal generation module (304; 604) is configured to provide a test signal to a remote antenna unit (208a;...; 208f) of the telecommunications system, wherein the test signal generation module (304; 604) comprises: a first signal source configured to generate a first signal component; a second signal source configured to generate a second signal component; a combiner configured to generate the test signal by combining the first signal component and the second signal component; wherein the intermodulation detection sub-system (103; 103'; 103") further comprises a first signal source configured to generate a first signal component; a second signal source configured to generate a second signal component; a combiner configured to generate the test signal by combining the first signal component and the second signal component; wherein the intermodulation detection sub-system (103; 103'; 103") further comprises at least one intermodulation detection device integrated into the telecommunications system, wherein the at least one intermodulation detection device is configured to detect intermodulation products generated by mixing the first signal component and the second signal component of the test signal, wherein the at least one intermodulation detection device is integrated into at least one of the remote antenna unit (208a;...; 208f) or the unit of the telecommunications system; and a controller integrated into the unit of the telecommunications system, wherein the controller is configured to control the test signal generation module (304; 604) and the at least one intermodulation detection device and wherein the controller is further configured to select a first frequency of the first signal component and a second frequency of the second signal component such that the sum or difference of the first frequency and the second frequency is a third frequency in an uplink frequency band, the intermodulation detection sub-system being characterized by a frequency scanner configured to detect an extraneous signal in a coverage area of the remote antenna unit (208a;...; 208f), wherein the controller is configured to select the first frequency and the second frequency such that the third frequency is different from a frequency of the extraneous signal.