<p>A method and apparatus for producing an effect of a chemical or biochemical agent on a system responsive to such agent, are disclosed. In practicing the method, a plurality of low-frequency time-domain signals of the agent are generated, each at a different at a different noise level within a selected noise level range. The signals are analyzed by producing spectral plots of the time-domain signals, and identifying an optimized agent-specific time-domain signal based on information in the spectral plots. A chemical or biological system responsive to the agent is exposed to the optimized time-domain signal by placing the system within the magnetic field of an electromagnetic transducer, and applying the signal to the transducer at a signal amplitude and for a period sufficient to produce in the system an agent-specific effect on the system.</p>
