of the routine set forth in flowchart 220 as was described above in connection with fig3 the self diagnostic system of the present invention determines if the amplitude and frequency of signal 104 meets the criteria of falling within the safe magnitude range and not causing the driver 32 to exceed acceptable power limits these determinations are made by the steps in flow diagram 220 if the initial amplitude and frequency selected for signal 104 is such that the signal does not meet either or both criteria the amplitude or frequency is adjusted in a direction so as to cause the criteria to be met in step 224 the logarithmic data values that were stored in step 214 of fig4 are read by the diagnostic control algorithm in step 226 the data values are sorted to find the frequency component that has the largest magnitude that component corresponds to magnitude 100a of fig2 and 2a the routine then proceeds to a series of steps wherein it asks the questions 1 does the amplitude of the determinant signal satisfy the margin 1 criteria and 2 does the amplitude of the determinant signal satisfy the margin 2 criteria the first question is asked in step 228 wherein it is determined if the difference between the absolute value of the amplitude of the signal 104 and.