TABLE OF CONTENTS The open-loop concept of oscillator design is often met with considerable skepticism by engineers familiar with classic oscillator terminology. For comfort consider Figure 2-4A where the oscillator cascade is drawn with only the RF components. Next, the circuit is redrawn in Figure 2-4B with the output connected to the input and the ground floated. In Figure 2-4C the emitter is selected as the ground reference point. Notice the configuration is the familiar common-emitter Pierce oscillator. In Figure 2-4D the circuit is again redrawn, this time with the base selected as ground reference. The result is the familiar common-base Colpitts. These open-loop, Pierce and Colpitts oscillators are in fact the same oscillator!
