Design of Tunable F-P Filter Driver Based on FPGA

The special driver for tunable F-P filter is expensive, so it has an important application value to design a driver with stable performance and low cost. In this paper, the field programmable gate array (FPGA) was chosen as the core chip to constitute triangular signal generator based on direct digital frequency synthesizer (DDS). The output frequency of waveform ROM look-up table will be altered by changing frequency control word. Then, the products of amplitude word and signals of ROM table output were transmitted to DAC to be converted into analog signal. The variable frequency and amplitude modulation signals were got after smoothed by low pass filter. The frequency range of driving signal is 1 Hz~10 KHz, and the resolution of frequency is 0.1 Hz. The amplitude range is 1 V~10 V, and the resolution of amplitude is 0.1 V. The simulation and experimental results show that the driver has the characteristics of simple structure, stable signal, adjustable frequency and amplitude and lower cost. It can satisfy the requirements of tunable F-P filter driven in practical engineering.