Wide frequency oscillator
Posted on Nov 29, 2012 5295
An oscillator/amplifier is resistively tunable over a wide frequency range. Feedback circuits containing operational amplifiers, resistors, and capacitors synthesize the electrical effects of an inductance and capacitance in parallel between the input terminals. The synthetic inductance and capacitance, and, therefore, the resonant frequency of the input admittance, are adjusted by changing a potentiometer setting.
The input signal is introduced in parallel to the noninverting input terminals of operational amplifiers Aj and A2 and to the potentiometer cursor. The voltages produced by the feedback circuits in response to input voltage V^ are indicated at the various circuit nodes.