| 摘要 |
PURPOSE:To prevent an hFE characteristic from being deteriorated due to the increase in an emitter potential at the peak of an oscillating voltage by connecting an emitter of a local oscillating transistor (TR) and an output side of a mixer diode via a resistor. CONSTITUTION:A resonance inductance 6 connected to a collector of the local oscillating TR5 is connected electromagnetically to a lead wire of the mixer diode 3 and an output frequency of a local oscillating stage 2 is fed to the mixer diode 3. The emitter of the local oscillating TR5 is connected to an output terminal 4 of the mixer diode 3 via a resistor 16 in a tuner constituted in this way. As a result, a negative voltage is obtained at an output of the mixer diode 3 as an oscillating voltage of the local oscillation stage 2 increases and since the negative voltage is fed to an emitter of a TR5 via the resistor 16, the deterioration of the hFE characteristic is prevented because of the emitter voltage exceeding the base voltage at the peak of the oscillating voltage. |
