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 downlink path of the telecommunications system, wherein the test signal generation module (304; 604) comprises: a first signal source configured to generate a first signal component of the test signal, and a second signal source configured to generate a second signal component of the test signal; an intermodulation detection device communicatively coupled to an uplink path of the telecommunications system, wherein the 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 and having a third frequency that is the sum or difference of the first and second frequencies; 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 intermodulation detection device, wherein the intermodulation detection sub-system is characterized in that 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 third frequency is at a frequency in an uplink frequency band while avoiding frequencies of extraneous signals from wireless devices in a coverage area serviced by the telecommunication system. 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 downlink path of the telecommunications system, wherein the test signal generation module (304; 604) comprises: a first signal source configured to generate a first signal component of the test signal, and a second signal source configured to generate a second signal component of the test signal; a first signal source configured to generate a first signal component of the test signal, and a second signal source configured to generate a second signal component of the test signal; an intermodulation detection device communicatively coupled to an uplink path of the telecommunications system, wherein the 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 and having a third frequency that is the sum or difference of the first and second frequencies; 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 intermodulation detection device, wherein the intermodulation detection sub-system is characterized in that 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 third frequency is at a frequency in an uplink frequency band while avoiding frequencies of extraneous signals from wireless devices in a coverage area serviced by the telecommunication system.