| 摘要 |
PROBLEM TO BE SOLVED: To provide a feedback signal processing circuit having a transfer function with a modified loop gain so that the transmission gain in a passing frequency region becomes negative feedback no greater than a forward gain, so as to obtain a low noise characteristic. SOLUTION: The feedback signal processing circuit includes a forward circuit for applying a predetermined transfer characteristic to an input signal, so as to output with a predetermined gain, and a feedback circuit for negative feedbacking a portion of the output of the forward circuit to the input signal. The forward circuit is a current-controlled voltage output circuit, including a base-grounded transistor to which the input signal is input, a circuit having a transfer impedance characteristic, and an emitter-follower transistor for outputting voltage. The above current-controlled voltage output circuit may also be configured by use of an operational amplifier. The transfer impedance characteristic is achieved by a variety of types of high-pass, low-pass and band pass filters. COPYRIGHT: (C)2007,JPO&INPIT
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