| 摘要 |
PROBLEM TO BE SOLVED: To realize an input circuit which has wide-band frequency characteristics, enlarges the range of input voltages and enhances input impedance. SOLUTION: The present invention improves on an input circuit which outputs from an output terminal an output signal resulting from differentially amplifying a first signal and a second signal inputted from two input terminals, respectively. The present circuit comprises: a differential amplifier circuit for outputting a differential signal as a single end signal; an attenuation circuit which attenuates the first signal and outputs it to the differential amplifier circuit; a capacitor of which one end is connected to one input terminal and the other end is connected to an output side of the differential amplifier circuit and which transmits a high frequency signal in the first signal; a buffer to which the single end signal from the differential amplifier circuit and the high frequency signal from the capacitor are inputted and which outputs an output signal; and a feedback circuit which feeds back the output signal from the buffer and outputs the signal to the differential amplifier circuit together with the second signal. COPYRIGHT: (C)2005,JPO&NCIPI
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