A non-linear transconductance amplifier includes a differential input stage and a non-linear transconductance stage operatively coupled to the differential input stage. The differential input stage includes first and second inputs forming a non-inverting input and an inverting input, respectively, of...http://www.google.com.tw/patents/US6650182?utm_source=gb-gplus-share專利 US6650182 - Exponential transconductance amplifier
