许多研究人员已经将基于发光二极管的可见光通信(VLC)与照明通信相结合, 然而VLC系统的性能主要受限于系统带宽和信噪比(SNR),之前的实验并没有充分利用信道资源，特别是SNR资源。 针对SNR资源利用问题，文章提出了一种基于时间的混合调制无载波幅度相位VLC系统, 在该系统中，信号的实际调制级别不仅可以是一个整数，而且可以是一个十进制数，通过按一定的比例对比特进行分组，可以提高信道的SNR资源利用率。 通过仿真和实验验证了该系统的可行性和有效性。实验结果表明，当驱动信号的峰峰值电压范围为0.65~0.86 V时，可以获得约10％的比特率改善。

Light Emitting Diode (LED) -based Visible Light Communication (VLC), combining with communication with illumination, has been attracted much attention recently. The performance of VLC system is mainly subjected to the limited system bandwidth and Signal-to-Noise Ratio (SNR). However, the previous studies do not make full use of channel resources, especially the SNR resources. In this paper, for the issue of utilization of SNR resource, a time-based hybrid modulation carrier-less amplitude phase (CAP) VLC system is proposed. In this system, the real modulation level of the signal can both be an integer a decimal number, which increases utilization of the SNR resources of the channel by grouping bits by a certain ratio. The feasibility and effectiveness of this system are verified through both simulation and experiment. The bit rate can be improved by ~10% when peak-to-peak voltage of driving signal ranges from 0.65 V to 0.86 V in experimental demonstration.