A system comprises a modulator circuit, a test signal generator circuit, and a control circuit. The modulator circuit is operable to generate a data-carrying signal based on a reference signal. The test signal generator circuit is operable to generate a test signal based on the reference signal. The control circuit is operable to determine current status of a microwave backhaul link. The control circuit is operable to configure a nominal frequency at which the test signal generator circuit generates the test signal based on the determined status of the microwave backhaul link. The control circuit is operable to determine an amount of whitespace to have on either side of the test signal based on the current status of the microwave backhaul link. The control circuit is operable to configure the modulator circuit such that the data-carrying signal has the determined amount of whitespace surrounding the nominal frequency of the test signal.