Fm receiver

Abstract

Abstract PURPOSE:To prevent the increase of the distortion factor at a large input signal by connecting emitters of transistors(TRs) for high frequency amplifier with the mixer of an FM receiver in terms of DC, providing a resistor between a connecting point and ground so as to make the emitter potential of both TRs equal to each other. CONSTITUTION:The emitter of a high frequency amplification and the emitter of a mixing TR 12 are connected in terms of DC and both emitters are connected to ground via a common resistor 17. When an input voltage of a receiver is going to increase and the operating point of the TR 12 is going to be deviated, the gain of the TR 11 is lowered and the input voltage of the TR 12 is decreased. Moreover, an emitter of a local oscillation TR 13 is connected to the emitters of the TRs 11, 12 in figure, but no practical problem is caused even if they are not connected but used as independent bias circuits. Thus, the deviation of the operating point of the TR 12 of a frequency mixer circuit 3 is suppressed simply even at the reception of a large input signal and the increase of the distortion factor and the deterioration in the cross modulation characteristic are prevented.

Inventors

• 👤 Naoki Hirasawa
• 👤 直樹 平澤

Bibliographic Details