A complex network can be interpreted as a connection consisting of two real networks, one of which transfers the real part of the complex signal and the other transfers the imaginary part. In this paper, a realization of complex filters using wave digital lattice filters is reported. The relation between the real part and the imaginary part of its output fulfills the Hilbert transformation. As the attenuation response of a wave digital lattice filter meets some symmetrical requirements, a certain amount of hardware can be saved. Explicit formulae and the Hilbert transformer table are given. The disgn process is so simple that a pocket programmable calculator is sufficient to carry out the necessary calculations.