| 摘要 |
PURPOSE:To ensure the excellent output for the FM and AM circuit by extracting the FM detection output with the operation stopped for the constant voltage source for the AM circuit and then lowering the base bias of the transistors such as the IF amplifier circuit or the like for the FM circuit. CONSTITUTION:With opening of band change-over switch d, constant voltage source IV stops the operation. Thus no bias is given to the base of transistor TrQ16, and FM detection output signal is delivered through output terminal (c). On the other hand, with closure of switch (d), source IV starts the operation to give the bias to the base of TrQ16 and thus to turn on the transistor. At the same time, the base bias is lowered down for IF amplifier circuit I plus TrQ5, Q6 and Q7 each to stop each operation, and thus the detection output signal of TrQ14 is delivered through terminal (c). As a result, the excellent output is secured from the FM and AM circuits. |
