摘要 |
<p>The invention can be related to the technical field of implementation and control of electrically controllable active filters. In accordance with the invention filters are controlled and implemented with the aid of a differential gain stage. Said stage includes pairs of like amplification components (QI11 and QI21, QI12 and QI22, QI13 and QI23), and groups of series-connected diode components as well as at least one current generator (Q1, Q2, Q3). The forward voltage drop of the diode components has the same current responsiveness as the base-emitter voltage of the amplification components. A filter of the first order includes a differential gain stage with a capacitive component (C) connected across the output of said stage or to its amplification components. A filter of the second order can include two differential gain stages, each with its capacitive component (C1, C2) in circuit. An oscillator for controlling filters can comprise three series-connected low-pass filters each including its differential gain stage.</p> |