A simple configuration for realizing voltage-controlled impedances

A simple configuration is proposed that incorporates an effective cancellation of the nonlinearity of the V/sub DS/-i/sub D/ characteristics of the FET to produce a voltage-controlled resistance (VCR) with linear range considerably more extended than other conventional FET-based VCRs. The configuration is shown to be simpler than op-amp-JFET based VCRs yet is more versatile than the previously known circuits. It makes possible the realization of VCC and VCL elements from the same configuration, which cannot be realized from the earlier circuits. CMOS versions of the proposed schemes of the VCC and VCL are suggested.<
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