In this project, the WKB tunneling model is combined with classical single particle model to describe the CDW transport. The calculated DC and AC conductivity agree with the experimental results in the low field and low frequency domain \cite{Gr_ner_1981}. The mixed signal conductivity is also calculated with the noticeable resonant ridge above threshold voltage and photon-assisted tunneling in the low field domain. The reasons for the disagreement of the harmonics and the ratio of amplitudes are largely because of the incompleteness and simplification of the discussion and the inaccessibility of some parameters.