Low-noise active rc signal processing circuit

Abstract

Disclosed is a low-noise active RC signal processing circuit, which comprises a feedforward section operable responsive to an input signal to provide an output at a predetermined gain, and a feedback section operable responsive to the output of the forward circuit to negatively feed back the output to the input signal of the feedforward section while giving a predetermined transfer characteristic to the output, so as to allow the processing circuit to have a transfer impedance characteristic equal to or less than the predetermined gain over the entire frequency range. The feedforward section is composed of a current-controlled voltage output circuit which includes a common-base transistor for receiving and inverting the input signal, and an emitter-follower transistor for outputting voltage, and has a transfer impedance defining the predetermined gain. The current-controlled voltage output circuit may also be constructed using an operational amplifier. Various filters, such as a bandpass, lowpass or highpass filter, can be achieved by arranging the transfer impedance characteristic. The present invention can provide an active RC signal processing circuit having a low Q-value and an excellent low-noise performance.

Dependencies are inferred from the claim text.