Variable reactance tuning for a resonant circuit

摘要

A tuning arrangement for a resonant circuit, having an output reactance dependent upon a plurality of input applied signals one of which is an input tuning signal. An array of tuning circuits is connected in a network whose output reactance is used to control the resonance frequency of the resonant circuit, each tuning circuit having a control input N0-N11 and having a reactance V0-V12 which varies in dependence upon the value of a control signal applied to the control input. A plurality of different control signals is generated for application to the control inputs of the tuning circuits. Each such control signal varying substantially linearly with the input tuning signal throughout a predetermined range specific to that control signal, so that the frequency response of the resonant circuit to the input tuning signal is substantially linear throughout a desired range of the input tuning signal. The tuning circuits are preferably variable reactance elements such as MOS varactors and further control signals can be applied to control higher order components.