| 摘要 |
<p>An amplifier having a high input impedance and a low output impedance in the voice band. The circuit comprises an input coupling circuit (101a) and a similar coupling circuit (101b), source of reference direct current voltage (103), and a gain providing circuit (102). The coupling circuits (101a and 101b) comprise a first pair of diodes (Q1 and Q2) symmetrically placed about one input terminal (IN1). Outputs of the reference voltage source (103) are provided to coupling circuits (101a and 101b) and through the coupling circuits to a gain providing circuit (102). Such an arrangement facilitates power supply noise rejection and automatic cancelling of direct current voltage drifts.</p> |
