Design of Sinusoidal Signal Generator Based on Two-wire Transmitter

For the poor signal quality in remote communication of voltage transmitter, a two-wire resistance-to-current transmitter with its input resistance of 1KΩ-2KΩ and its output current of 4 mA -20 mA, is proposed in this paper. The chip AD9851, which is a direct digital synthesizer (DDS), is controlled by the transmitter for a long distance. And then a sinusoidal signal with 1MHz-2 MHz is generated by the AD9851. The practice proved that sinusoidal signal generator was controlled by the two-wire resistance-to-current transmitter in the process of remote data transmission. And moreover, the non-linearity of resistance and frequency were perfect.