| 摘要 |
PROBLEM TO BE SOLVED: To stabilize a filter circuit to desired characteristics without increasing circuit scale. SOLUTION: This active filter circuit 14 includes a current control part 30, a first Gm-C filter part 32 and a poststage circuit 34. The current control part 30 outputs adjustment current for adjusting Gm values corresponding to each transconductance amplifier to the first Gm-C filter part 32 using a signal output from a central control part 20 as input. The poststrage circuit 34 includes load capacity comprised of an active element such as a transconductance amplifier. The first Gm-C filter part 32 is constituted of a plurality of transconductance amplifiers and a control part which controls the Gm value of the transconductance amplifiers, restricts bands of a signal output from a first filter signal selection part 12 to output it to the poststage circuit 34. COPYRIGHT: (C)2007,JPO&INPIT
|
