| 摘要 |
A pre-amp circuit including a photodiode, first and second amplifiers and a differential amplifier reduces or eliminates noise in an input signal. The photodiode converts an external optical signal into an electrical signal which includes noise. The first amplifier amplifies the difference between an output voltage of the photodiode, including the noise, and the reference voltage, to generate a difference signal which includes a first noise component. The second amplifier buffers the reference voltage to generate a signal which includes a second noise component which is in-phase with the first noise component. The differential amplifier amplifies the difference between the voltages output from the first and second amplifiers to generate an output signal which is substantially devoid of such noise. The present invention is amenable to application in remote control receiver systems.
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