| 摘要 |
PURPOSE:To improve the talking quality such as clear articulation by providing a function capable of varying the frequency characteristic to a reception amplifier. CONSTITUTION:The titled amplifier consists of a preamplifier circuit PAC comprising preamplifiers PRA1-PRA3 connected in cascade, an output circuit amplifying an output of the preamplifier circuits and supplying the result to the receiver, a bias circuit VRB supplying a bias voltage to the preamplifiers PRA1-PRA3 and a constant current source supplying a constant current to the bias circuit VRB. The frequency characteristic is corrected to that in response to the individual difference by adjusting the gain characteristic and the resonance frequency of the preamplifiers PRA1-PRA3.
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