In this paper, the microwave frequency division multiplexing (FDM) scheme and associated radio-frequency (RF) circuitry of the SLAC Microresonator Radio Frequency (SMuRF) system to enable high-volume readout of cryogenic transition-edge sensors (TES) are discussed. This system, planned to be deployed to the Simons Observatory for Cosmic Microwave Background (CMB) imaging, will enable the next generation of x-ray imaging applications. Qualification testing methods of the RF subsystem are also presented.