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9-3: Frequency Conversion
Local Oscillator and Frequency Synthesizers: LC Oscillator
A local oscillator is sometimes referred to as a variable-frequency oscillator, or VFO.
An amplifier (e.g. FET) is connected as a Colpitts oscillator.
Feedback is developed by a voltage divider made up of capacitors.
The frequency is set by a parallel tuned circuit.
The output is taken across an RFC and it is buffered by a direct-coupled emitter follower.