Until recently, there was no technique to adequately validate many nonlinear models of a device/system in CAD. This method represents the device's nonlinearity as a finite Volterra series and uses a multi-tone test signal to measure the Volterra kernels. In contrast to previous work, no assumptions are made about the kernel's form; thus, measurements are useful for complex systems where no simple model is obvious. Currently, the technique is applied to low-frequency devices (acoustic tranducers and audio signal processors) with subtle nonlinearities. Signal generation/acquisition and processing equipment have restricted the characterization of the high/very high frequency devices commonly used in CAD, VLSI, and communications circuits. The proposed equipment would permit the study of models for devices operating up to 1 GHz and models which incorporate stronger nonlinearities. A system is specified that is composed of LeCroy Research Corp. high speed CAMAC modules for very high speed waveform input (1 GHz aggregate sample rate, 8-bit word) and output; and a Masscomp real-time UNIX Computation System for control of the CAMAC crate (via IEEE-488 interface), lower speed high resolution studies (imHz 12-bit word), computation, and kernal display.
