| 摘要 |
<p>A digital automatic gain control circuit provided with a first AGC loop and a second AGC loop; activated alternately. The first AGC loop is activated when an input signal is initially supplied. The loop produces a certain digital value calculated as an inverse number of the digital level of the input through predetermined digital arithmetic operations utilizing an approximation polynominal. The calculated digital value is then preset in certain portions of the second AGC loop. The second AGC loop starts operating by using said present value, then uses the digital level of the input itself, instead of the preset value, and produces an automatic gain controlled digital output. Utilizing said preset value as an initial input to the second AGC loop allows for rapid stabilization of the automatic gain controlled digital output.</p> |
