An Integratable Reactance Control for Color Subcarrier Regeneration

A synchronous switching technique is presented as an alternate to the voltage variable capacitance diode or reactance tube. The system shown does not require special components and lends itself to integration. The maximum and minimum effective capacitance values become independent variables and not a primary function of the reactance device. Examples of a 3.58 megacycle per second Clapp crystal oscillator and reactance combination are shown and the results plotted; but the technique can be applied to any usable frequency.