This paper presents a new FPGA based solution of the Low Level RF Control System for the TESLA Test Facility. The LLRF Control System is responsible for maintaining the constant amplitude and phase of accelerating field in the cavities in the accelerator's cryomodules driven by single klystron (up to 32 cavities). To obtain shorter processing time and less complicated hardware an FPGA based solution was selected. The proposed simulation has been simulated in software, and appeared to be faster and less complex than DSP based solutions