Patent ID: 7206030

Claim:
A signal amplitude controlling method for use in a system having an overall gain expressible as the product of a coarse analog gain and a fine digital gain, the method comprising the steps of: monitoring an input video signal for determining a desired overall gain value; determining an unfiltered fine gain control value using a first-order filter coefficient of unity and a first coarse gain control value; monitoring the unfiltered fine gain control value for underflow and overflow outside of a desired range; in the event no underflow or overflow occurs, using the first coarse gain control value as a second coarse gain control value, and a filter coefficient of less than one to determine a second fine gain control value; in the event underflow or overflow occurs, using the unfiltered fine gain control value and the first coarse gain control value to determine a second coarse gain control value; using the second coarse gain control value, determining a second fine gain control value; applying the second coarse gain control value and the second fine gain control value to the input video signal to produce an output video signal within a pre-selected output amplitude range.