Suppose a technician connected a potentiometer to the input of a VCO, to act as a manually-variable voltage source. Then, the technician compares the output of the VCO with an external signal source that slowly changes frequency, adjusting the potentiometer to keep the two frequencies equal:



If a voltmeter were connected between the potentiometer wiper and ground, what would its indication represent (with regard to the external audio signal)?



Explain where feedback occurs in this system, and how the system may be automated so as to not require the continual attention of a technician.