| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a compact digital AGC circuit requiring no multiplier for operation, such as gain calculation. <P>SOLUTION: The digital AGC circuit comprises: a ΣΔ modulator 61 composed of a D/A conversion means 43 for outputting an amount of charge of at least two levels, an integration means 44 for adding/integrating a signal output from the D/A conversion means 43 and a signal input from the outside to hold an integrated value, a comparison means 45 for comparing the integrated value output from the integration means 44 with a prescribed value, and a D/A switching means 46 for switching the output of the D/A conversion means 43 according to the output of the comparison means 45; an amplitude detection means 71; a gain calculation means 72; a substitution operation means 73; a digital filter 48; and a timing control means 93 having a PLL circuit 91. <P>COPYRIGHT: (C)2009,JPO&INPIT |
