Digital frequency conversion technique in HDTV

This paper makes a research on the fundamental principle of digital modulation and frequency conversion in broad band digital broadcasting-terrestrial TV ( BDB-T) system. Different from conventional down-conversion technique, this paper proposes a new digital down-conversion model utilizing Hilbert transform and a method eliminating the A/D DC offset in this model is also proposed. The correspondent FPGA hardware though testing process in HDTV prototype proves the efficiency and good performance of the model and the new method.