Title:
ACTIVE FILTER CIRCUIT
Document Type and Number:
Japanese Patent JP2783301
Kind Code:
B2
Abstract:
PURPOSE: To obtain an active filter circuit which accurately sets the cut-off frequency to a prescribed value without adjusting and has the good temperature characteristic of the cut-off frequency and is suitable for an IC.
CONSTITUTION: A signal is inputted from a first signal input terminal 1 or a second signal input terminal 18 and is outputted from a signal output terminal 16. A cut-off frequency fC of a filter is a function of a transmission conductance gm of a voltage controlled current source 15. The transmission conductance gm is changed by a potential difference VC applied between a first control terminal 10 and a second control terminal 12. The potential difference between the cathode of a first diode 34 and that of a second diode 35 in a control circuit 31 is VC. The cut-off frequency fC of this active filter circuit is set to the prescribed value with a high precision by the control circuit 31, and the temperature characteristic is improved.
Inventors:
HAYASHI JUICHI
Application Number:
JP21477391A
Publication Date:
August 06, 1998
Filing Date:
July 31, 1991
Export Citation:
Assignee:
MITSUBISHI DENKI KK
International Classes:
H03H11/04; H03H11/12; (IPC1-7): H03H11/12
Domestic Patent References:
| JP2268507A |
Attorney, Agent or Firm:
Miyazono Junichi
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