To meet the high-speed and high-capacity demands of communication， a 300GHz electronic wireless transmission system for terahertz frequencies is proposed， which incorporates Probability Shaping （PS）， Discrete Multi-tone Modulation （DMT） and DFT-Spread （DFT-S） techniques. PS increases the Euclidean distance between constellation points， thereby enhancing the receiver sensitivity. In the system at most 55% bit error rate is decreased， enabling to extend transmission range. DFT-S technique reduces 1.68 dB peak-to-average power ratio of Orthogonal Frequency Division Multiplexing （OFDM） signals in the system， thus improving their resistance to nonlinear effects. By integrating these advanced digital signal processing techniques， 12GBaud PS-16QAM OFDM-DMT signals and 10GBaud PS-64QAM DFT-S-OFDM-DMT signals were successfully implemented in 1 m wireless transmission. Finally， the performance advantages of these digital signal processing techniques were compared.