JPS6188333U

JPS6188333U -

Info

Publication number: JPS6188333U
Application number: JP17199484U
Authority: JP
Priority date: 1984-11-13
Filing date: 1984-11-13
Publication date: 1986-06-09

Description

[Brief explanation of drawings]

第１図は本考案に係るアクテイブフイルターの
実施例を示す概略ブロツク回路図である。そして
、第２図は従来技術ないし背景技術を説明するた
めのものであつて、一般的なバンドパスアクテイ
ブフイルターの概略回路図を示している。１…アクテイブフイルター回路、２…周波数特
性制御回路、３…位相同期ループ、３Ａ…位相比
較器、３Ｂ…ＤＣ増幅器、３Ｃ…電圧制御型発振
器、Ｐ…基準周波数信号、ｆｏ…基準周波数、ｆ
…代表周波数。 FIG. 1 is a schematic block circuit diagram showing an embodiment of an active filter according to the present invention. FIG. 2 is for explaining the prior art or background technology, and shows a schematic circuit diagram of a general bandpass active filter. DESCRIPTION OF SYMBOLS 1... Active filter circuit, 2... Frequency characteristic control circuit, 3... Phase locked loop, 3A... Phase comparator, 3B... DC amplifier, 3C... Voltage controlled oscillator, P... Reference frequency signal, fo... Reference frequency, f
...Representative frequency.

Claims

[Scope of utility model registration request]

When a reference frequency signal is input to the phase comparator in a phase-locked loop formed by loop-connecting a phase comparator, a DC amplifier, and a voltage-controlled oscillator, the voltage output from the DC amplifier in the phase-locked loop, By supplying a frequency characteristic control circuit for an active filter circuit consisting of a resistor, a capacitor, an amplifying element, etc., a representative frequency such as a cutoff frequency or a center frequency that determines the frequency characteristic of the active filter circuit is phase-compared in the phase-locked loop. An active filter characterized in that it is configured to automatically match the frequency of a reference frequency signal input to the filter.