Comments on “Cancellation of OpAmp Virtual Ground Imperfections by a Negative Conductance Applied to Improve RF Receiver Linearity” [

In the above paper [1], not only [2] but also older papers [3]-[5] exploiting a negative impedance connected to the virtual ground node should have been included as references. As discussed more extensively in a recent book [6], all these papers aim at mitigating the virtual ground imperfections using a grounded negative conductance. This technique was first proposed by Boutin [3] under the name “active compensation” using a “NIC” (Negative Impedance Converter). Later,other authors [4], [5] have studied the technique, and have shown that this results in an inverting amplifier with frequency dependent gain, which exhibits low magnitude and phase errors compared to uncompensated inverting amplifiers [6].