近期以低軌道通訊衛星群提供全球隨時隨地高資料率行動上網技術成為熱門的研究課題與技術發展方向，於是採用第二代數位廣播 (DVB-S2)，除了QPSK，更提供 8PSK、16APSK、32APSK等多種調變方式，更能適應線性特性相對不好的衛星傳輸通道。 本論文在RFSoC平台實現DVB-S2之收發機。在發射機中，包含了BCH code、LDPC code和調變器，接收機則包含時間同步、頻率同步、相位同步，時間同步採用內插器，以消除時序偏移並進行同步取樣，頻率同步則是以固定星座圖去計算及修正頻率偏移，相位同步則是以已知的Start Of Frame (SOF) 來修正相位，並增加自動偵測調變機制 (MODCOD-Detector) ，以便後續解碼器所用，將其整合實現DVB-S2收發機。並實現數位中繼器 (Digital Repeater) 的應用，可應用在衛星酬載中用以重新產生任意調變及碼率之訊號，獲取之訊號放大以及重新產生，使得訊號恢復強度以及質量，降低傳輸時訊號衰減以及失真的影響在高速傳收上增進訊號之品質。;Recently, providing high data rate mobile internet access anytime and anywhere through low Earth orbit communication satellite networks has become a popular research topic and technical development direction. The second-generation digital broadcasting (DVB-S2) is adopted, which provides multiple modulation methods such as QPSK, 8PSK, 16APSK, and 32APSK to adapt to satellite transmission channels with relatively poor linear characteristics.
This paper implements a DVB-S2 transceiver on the RFSoC platform. The transmitter includes BCH code, LDPC code, and modulator, while the receiver includes time synchronization, frequency synchronization, and phase synchronization. Time synchronization uses an interpolator to eliminate timing offset and perform synchronous sampling. Frequency synchronization uses a fixed constellation diagram to calculate and correct frequency offset. Phase synchronization corrects the phase using the known Start Of Frame (SOF) and adds an automatic modulation code (MODCOD-Detector) detection mechanism for subsequent decoder use, integrating it into the DVB-S2 transceiver implementation. The paper also implements the application of a Digital Repeater, which can be used in satellite payloads to regenerate signals of any modulation and code rate. The obtained signal is amplified and regenerated, restoring signal strength and quality, improving signal quality for high-speed transmission and reception, and reducing the effects of signal attenuation and distortion during transmission.
