Design of PCM/FM Baseband Modulation Transmitter Based on Software Radio

The PCM-FM system telemetry is the most widespread system in the field of aerospace telemetry in the day. However, the characteristics of traditional analog circuits make the system less flexible, the layout of the circuit is difficult, and the low-frequency response characteristics are not ideal. In response to the problems above, this paper uses a fully digital FPGA to implement the PCM-FM algorithm, with high accuracy, parameterized configuration and other features. Telemetry form is flexible and easy to debug. And it is easy to receive and send signals at both ends of the digital processing. The experimental results show that the use of FPGA chip to achieve digital signal processing algorithm for PCM-FM full digital baseband modulation can meet the requirements of a wide range of 1kbps~10Mbps baseband rate modulation.