中文摘要：

设计了一种基于数模同播结构的新型FM发射机，该结构可以实现在现有模拟FM广播频段上同时传输数字音频广播信号。该结构由FPGA和两路ADC组成，基于NiosII软核CPU搭建控制平台，利用DDS和IFFT的原理分别实现模拟FM调制和数字OFDM调制，最后合路实现数模同播。通过实验证明，该结构具有实现简单、不需要申请新的频谱资源和拓展高音质数字广播业务的特点，可以实现模拟／数字调频同播运行，为FM广播由模拟向数字平滑过渡提供了实验验证。

英文摘要：

A new FM transmitter based on digital -analogue simulcast structure is proposed in this paper. On the premise of not affecting the existing analogue broadcasting, the digital - analogue simulcast provides high - resolution digital audio broadcasting and data services with its analogue broadcasting spectrum. The system can be divided into the FPGA module and dual - ADC module, which consists of a control module based on the Nios II CPU. Analogue FM signal can be generated by the principle of DDS and digital OFDM signal can be also generated by the principle of IFFT, and then the digital-analogue simulcast signal can be generated at last. Experimental results show that the structure is easy to implement and has the high quality digital broadcasting services without new spectrum resources. Analogue and digital signals can be broadcast synchronously in this experiment platform, which provides an experimental verification for smooth transition from analogue broadcasting to digital broadcasting.