Nonlinear dielectric spectroscopy is, potentially, a powerful non-invasive method of monitoring biological cell activity, with possible applications in biotechnology and in medicine. This paper describes the design and implementation of an integrated instrument for obtaining and analysing the nonlinear dielectric spectra of biological cell suspensions. The instrument is based on an IBMcompatible personal computer equiped with an AT&T digital signal processor and 16-bit analogue I/O. It allows collection of resultant power spectra in real time during optimal time sweeps over a wide range of excitation voltages and frequencies. Further analysis of the sets of spectra is undertaken by means of mutivariate calibration. Examples are included of results obtained and it concludes with a brief discussion of the present limitations of the method.
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