公开(公告)号：US3904978A

公开(公告)日：1975-09-09

申请号：US49563974

申请日：1974-08-08

Applicant: BELL TELEPHONE LABOR INC

Inventor： DANIELS RICHARD WILLIAM ,  KURTH CARL FERDINAND

IPC: H03H11/12 ,  H03F1/36

CPC classification number: H03H11/1295

Abstract: An active filter having a predetermined fourth-order transfer function is realized by employing a single gain unit, for example, a differential amplifier, in conjunction with two passive resistor-capacitor (RC) circuits. The RC circuits have pole-zero pairs which are widely separated in frequency. Consequently, each RC circuit does not cause appreciable distortion in the attenuation characteristic of the filter in the frequency band in which the other RC circuit is affecting the filter attenuation characteristic.

Abstract translation: 具有预定的四阶传递函数的有源滤波器通过采用单个增益单元（例如，差分放大器）结合两个无源电阻 - 电容（RC）电路实现。 RC电路具有极零对，在频率上分开。 因此，每个RC电路在其他RC电路影响滤波器衰减特性的频带中不会引起滤波器的衰减特性的明显失真。