| 摘要 |
PURPOSE:To facilitate the check of integrated circuit device comparatively large in scale and to improve the degree of circuit integration by providing the 1st, 2nd amplifier circuits, a gain control circuit controlling the gain of the 1st amplifier circuit, a voltage detection means and a gain fixing means for the 1st amplifier circuit. CONSTITUTION:A switching circuit 92 operated in response to a DC potential of a terminal 65 is provided and a voltage larger than a bias stabilizing voltage is fed forcibly to the terminal 65 by an external power supply 85 for adjustment at the operation check, selection, inspection and adjustment of an intermediate frequency amplifier circuit. The external power supply 85 conducts a Zener diode 81 and a transistor (TR) 82. Thus, the output of an AGC amplifier circuit 56 comprising a TR 83 and an emitter resistor 84 is suppressed to a low potential by the TR 82. Since the gain of the 1st stage 52 is set forcibly by the connection above, the operating state of the 2nd stage 52 and succeeding stages is known from the signal state of input/output terminals 62, 79 and from the output state of other terminals. Thus, each stage singly and the distribution of the AGC are checked easily.
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