Abstract An input signal is supplied to the non-inverting input terminal of a current differential amplifier (11). A capacitor (Co) is connected between the output terminal of the current differential amplifier (11) and a power source (vss) and the capacitor (Co) stores charges according to an output signal of the current differential amplifier (11). The input signal and an output signal of the current differential amplifier (11) are supplied to resistors (R₅, R₆) via buffer circuits (13, 14) and signals divided by the resistors (R₅, R₆) are added together by a buffer circuit (15) and output from an output terminal (OUT) and at the same time fed back to the inverting input terminal of the current differential amplifier (11).
An active filter characterized by comprising: a current differential amplifier (11) having an inverting input terminal, a non-inverting input terminal and an output terminal and supplied with an input signal at the non-inverting input terminal; a capacitor (Co) connected between the output terminal of said current differential amplifier (11) and a power source, for storing charges according to an output signal of said current differential amplifier (11); and an adding circuit for dividing the input signal and the output signal of said current differential amplifier (11) by means of resistors (R₅, R₆) and adding them together, an output signal of said adding circuit (12) being supplied to an output terminal (OUT) and to the inverting input terminal of said current differential amplifier (11).
Claim 2
Dependent Claim
130 words
An active filter according to claim 1, characterized in that said adding circuit comprises: a first buffer circuit (13) having an input terminal connected to the non-inverting input terminal of said current differential amplifier (11); a first resistor (R₅) connected at one end to an output terminal of said first buffer circuit (13); a second buffer circuit (14) having an input terminal connected to the output terminal of said current differential amplifier (11); a second resistor (R₆) connected at one end to an output terminal of said second buffer circuit (14); and a third buffer circuit (15) having an input terminal connected to the other ends of said first and second resistors (R₅, R₆) and an output terminal connected to the inverting input terminal of said current differential amplifier (11).
Claim 3
Dependent Claim
18 words
An active filter according to claim 1, characterized in that said power source is a ground potential (Vss).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.