| 摘要 |
An automatic chrominance control (ACC) circuit for a color television receiver is used with a chrominance amplifier in the form of an integrated circuit differential amplifier operated with a constant current source. In order to reduce the number of bonding pads required for the amplifier, the ACC control voltage and the input signal are applied in common to a bonding pad coupled to the base of one of the transistors of the differential amplifier. The other transistor is supplied with a biasing potential, and a resistor interconnects the bases of the transistors to prevent signal lockout by causing the transistor to which the signals are applied always to conduct the same or more current than the other transistor. Increased conductivity of the first transistor causes a reduced gain thereof due to the increased impedance appearing on its emitter when the other transistor is rendered less conductive.
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