结合离散正弦变换(DST)和离散余弦变换(DCT)，提出一种新的DST/DCT直流偏置-离散多音频(DC-DMT)调制方案。在不增加系统复杂度的情况下，该方案可拓展独立子载波的个数，有望提高可见光系统的传输速率。通过推导该调制方案下的误码率表达式及该调制信号峰均功率比（PAPR）的互补累积分布，分析了限幅噪声对离散多音频（DMT）、直流偏置光正交频分复用（DCO-OFDM）及非对称限幅光正交频分复用（ACO-OFDM）可见光系统误码率的影响。研究结果表明，理论分析的误码率与仿真结果一致，在相同的传输速率下所提方案误码率更低；PAPR的互补累积分布与调制阶数无关，但随子载波数N增加而增大，在N较大时理论分析与仿真结果吻合。误码率仿真结果表明，相同传输速率下DST/DCT DC-DMT与DCO-OFDM在低信噪比时误码率性能相当，均优于脉冲幅度调制-离散多音频（PAM-DMT）、DC-DMT及ACO-OFDM；在高信噪比时，限幅噪声会使系统误码率增大。

Combined with the discrete sine transform (DST) and discrete cosine transform (DCT), a novel DST/DCT direct current bias-discrete multitone(DC-DMT) modulation scheme is proposed. This method is able to expand the number of independent subcarriers without increasing the complexity of system, and it is expected to improve the transmission rate of visible light system. The bit error rate (BER) expression of the modulation scheme and the complementary cumulative distribution of peak-to-average power ratio(PAPR) are derived. The effects of clipping noise on the BER performance of DMT, direct current-biased optical-orthogonal frequency division multiplexing (DCO-OFDM) and asymmetrically clipped optical-orthogonal frequency division multiplexing (ACO-OFDM) visible light systems are analyzed. The results show that the theoretical BER is consistent with the simulation results, and the BER performance of the proposed scheme is better at the same transmission rate compared with that of other methods. The distribution of PAPR is independent of the modulation order but increases with subcarrier number N. When N is larger, the theoretical conclusions match the simulation results. At the same transmission rate, the simulation results show that the BER performances of DST/DCT DC-DMT and DCO-OFDM are similar in low signal-to-noise ratio (SNR), which are better than those of PAM-DMT, DC-DMT and ACO-OFDM; however, the BER performance degrades in high SNR due to the clipping noise.