HIGH FREQUENCY SIGNAL PROCESSOR

摘要

PURPOSE:To improve the unstable state of the operation by connecting a capacitor between a base and an emitter of a transistor (TR) of an intermediate frequency amplifier circuit. CONSTITUTION:A negative impedance viewed from the base of a TR31 of the intermediate frequency amplifier circuit is improved by connecting a capacitor 39 between the base and emitter of the TR31 and a positive feedback loop of an input terminal B of a double balanced frequency mixing circuit 1 and an emitter follower circuit 2 to an input terminal is interrupted. A value of 0.5pF- 1pF is sufficient to the capacitor 39 and even if the capacitor is constituted in an integrated circuit 4, the chip area is not remarkably increased. Moreover, the external pin number of the integrated circuit is not increased.