Common mode response effects in differential measurements

Differential measurements yield signals that are conditioned by differential or fully circuits which output depends on both the differential- and common-mode input voltages. carry desired information but voltages a nuisance their contribution to signal becomes an interference is usually evaluated from ratio between respective gains for voltages, Common-Mode Rejection Ratio (CMRR). Usually, only modulus of CMRR specified integrated amplifiers. In this paper we demonstrate response strongly component tolerance can be band-pass with gain peaking positive phase shifts inside passband signal. Tolerances as low ±0.01% cannot prevent close +90°. The presence in suspected whenever decreases frequencies below −3 dB bandwidth appraised alone. Surprisingly, high at worsen effect. Therefore, effects separate description inputs signals.