Design Of FPGA Based Signal Separator

In daily life many communication systems, such as remote control radios, usuallywork under half-duplex mode，whose sending and receiving state is controlled bytransmitting the PTT signal. In order to save the channel resources, the PTT signal isusually adopted as a harmonic signal with fixed frequency and transmitted with thespeech signal at the same time. To assure the normal work, the receiver should separatethe PTT signal reliably. So the research of technologies that can effectively and reliablyseparate PTT signal from the mixed signal is valuable.According to the overall design requirements, the development platform of thesystem is designed at first. Then the schematic of each module is presented andintroduced, including FPGA modules, signal processing module, power supply module,interface module, resetting circuit, and so on. Then the FPGA code design of the signalprocessing module is introduced in detail. The overall structure of the FPGA subsystemis designed, and also the communication interface of the data acquisition unit, FFTprocessing module, filter, and control interface of WM8731are also design and analyzed.The basic design idea of the FFT processor is introduced and the design of the IP core ispresented. The effects of different windows to the FIR filter are compared, and the Kaiserwindow based design scheme is selected.The designed FPGA based signal separator is implemented and simulated. Thesimulation results show that the designed system can separate the PTT signal from themixed signal effectively, the error between the calculated energy and real energy is under2percent, which meets the system requirement.