Abstract: The invention provides a radar system capable of transmitting data communications concurrently with and on a non-interfering basis with the normal radar functions. A continuous-wave carrier frequency is generated and transmitted to perform the normal radar function such as the processing of doppler data. For data communication purposes, the carrier signal is pulse modulated at selected pulse repetition frequencies with the selected PRF transmitted as first-order sideband components of the fixed carrier frequency. PRF selection is made in accordance with input digital data. A remotely-disposed command link receiver processes the incoming carrier wave and its sideband components to reconstruct the information contained in the transmitted data rates. Sensitivity and optimum detection by the command link receiver is achieved in a special manner that includes a phase locking of the received carrier frequency to the generated carrier frequency.