Discrete Automatic Gain Control with High Stability, High Speed and Low Distortion
High-speed automatic gain control (AGC) circuitry, capable of use in pulse of CW systems, incorporates hysteresis for improving the stability and distortion characteristics of the AGC. After a gain setting is selected, the built-in hysteresis feature prevents an adjustment in that gain setting until the amplitude of the input signal varies more than a predetermined amount. Sampling of the amplitude of the input signal and gain adjustments are accomplished by digital circuitry. In one embodiment, AGC is on a pulse-to-pulse basis.