(1),
(2). Typical experimental waveforms are shown in Figs. 8–10. A
bias network (BN) was used to slightly shift the zero point such
that frequency locking is obtained when there is a small phase
shift between the Comp1 and Comp2 signal. This was found
necessary for the compensation of the phase shift caused by the
parasitic capacitances of the diodes used as clamps (Fig. 7). This
phase offset was found to be constant and independent of load
resistance. Practical designs of this tracking system should attempt
to minimize this parasitic effect by choosing low capacitance
diodes.