| 摘要 |
<p>A constant bandwidth automatic gain control (AGC) system. The system is especially suitable for use in the positioning servo system of a magnetic disk storage system. The system includes a double balanced modulator circuit (U1) and a fixed gain video amplifier circuit (U2), and the gain thereof is set by a control voltage (Vc) derived from an otherwise conventional AGC loop (14, 24). The gain of the current steering stage of the double balanced modulator is limited to values no greater than 0.5. </p> |
