The first is the direct sample and hold circuit. When the sample and hold oscillator is high, and the switch is closed, the VCO tracks the pitch oscillator, and when the S&H oscillator goes low ...
After a brief failed experiment with a simple circuit built from discrete components, [GreatScott] turned his attention to voltage-controlled oscillators (VCO). He bought a couple of 5.8 GHz VCOs ...