The Realization of Narrow Bandwidth FSK Modulation in Radio Paging System

In this paper, the FSK(Frequency Shift Keying) modulation technology and the theory of its hardware basis, DDS(Direct Digital Synthesis), are introduced first Then a scheme to improve FSK spectrum efficiency utilizing DSP(Digital Signal Processor) to form a FIR(Finite Impulse Response) filter is proposed, and the actual electric circuit is given as well