| 摘要 |
An audio line receiver which tolerates a wide range of balanced and unbalanced source impedances with a minimal deterioration of the line receiver's common-mode rejection ratio. The line receiver includes a differential amplifier (50) with input amplifiers (52, 54) on each input of the differential amplifier. The input amplifiers are typically operational amplifiers (A8 or A9) connected for unity gain, but also having two bias resistors (R17 and R19, or R18 and R20) connected in series between the input terminals of the input amplifiers and ground. A capacitor (C1 or C2) connected from the output of the operational amplifier to a node between the two series connected bias resistors prevents the low impedance of the bias resistors from significantly degrading the line receiver's common-mode rejection ratio. |
