| 摘要 |
A method for providing DC offset trim for automatic gain controls independent of temperature or gain. A DC trim current is added or subtracted from one side of the differential AGC circuit. The trim current balances the currents through the two halves of the differential circuit, eliminating DC offset at the AGC output. The trim current is derived from a current source that is dependent upon another current source that provides the current through the two halves of the differential circuit. Therefore, the trim current responds to any changes in the current supplied to the differential AGC circuit. Thus, DC offset trim independent of temperature or gain, as well as reduction of the total harmonic distortion and direct DC coupling of signals between stages, is provided.
|
