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US 7,466,192 B2Granted
Low-pass filter and voltage-current conversion circuit used in the same
AssigneeOnkyo Corporation
InventorsMasatoshi Nakabo, Mamoru Sekiya, Masaaki Inoue
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AssigneeOnkyo Corporation
InventorsMasatoshi Nakabo, Mamoru Sekiya, Masaaki Inoue
Estimating the term…
A low-pass filter with a high signal-to-noise ratio is provided. A low-pass filter includes a first RC filter circuit, a differential operation circuit subtracting an output signal from a low frequency component of an input signal and outputting a differential signal, a second RC filter circuit, a voltage-current conversion circuit, and a capacitor. The voltage-current conversion circuit includes an operational amplifier, a first resistor, and a feedback circuit generating a feedback voltage in accordance with a voltage applied to the first resistor. If resistance values of first to fourth resistors are R1, R2, R3, R4, a relational expression of R1*R3=R2*R4 is satisfied, and output current i becomes constant regardless of a resistance value of a load resistance. Since only a first resistor is connected between the input and the output of the voltage-current conversion circuit, thermal noise decreases, and a signal-to-noise ratio becomes high.
A low-pass filter attenuating a high frequency component of an input signal and outputting a low frequency component of the input signal as an output signal, comprising:
A voltage-current conversion circuit converting a voltage into a current, comprising:
Dependencies are inferred from the claim text.