Non-linear modeling of a broadband SLIC for ADSL-Lite-over-POTS using harmonic analysis

A new frequency domain based identification algorithm for the discrete-time Wiener model is presented. The Wiener model belongs to the class of Volterra models with factorizable kernels. Opposed to the general Volterra model, it is shown that the Wiener model can be uniquely identified, using harmonic analysis only. Therefore the given identification scheme is very suitable for real world applications, where only measurements from the spectrum analyzer are available. The derived method is applied to model large scale analog circuits. A broadband SLIC (subscriber line interface circuit) for an ADSL-Lite-over-POTS (asymmetric digital subscriber line, plain old telephone service) central office application is considered. Data acquisition is done by an analog network simulator. Simulation results for an IIR (infinite impulse response) filter representation of the Wiener model are compared to results obtained from the network simulator and to measurements from the laboratory. Emphasis is put on the accuracy of the intermodulation products, occurring when a multi-tone signal is applied. To improve the model performance, a non-linear optimization procedure in the time domain is considered.