To satisfy the increase in demand for radio frequency (RF) spectrum, recent Federal Communications Commission (FCC) policies permit spectrum sharing between radar and Long-Term Evolution (LTE) communication systems. New cognitive radar systems are promoting spectrum sharing capabilities to mitigate the risk of mutual interference. To develop and test these systems, a realistic communications RF interference (RFI) environment is necessary. This paper describes a system, currently under development, to generate continuous dynamic 4G/LTE RFI for use by radar system designers. The system employs a Vector Signal Transceiver to emulate RFI with various frequency, time-complexity, and power parameters. Many 4G/LTE frames are pre-generated, then, according to the specified parameters, the random frame sequences are generated in real-time. This produces continuous, dynamic, and realistic LTE emissions for a controlled test environment. This work presents implementation details of the LTE emulation system.