Power supply ripple rejection in tuner oscillator stage

摘要

A bipolar transistor (Tr) in an oscillator stage of a tuner is provided with a diode (D10) in series with a resistor (R11) coupled between the base of the transistor (Tr) and the reference voltage to which the emitter of the transistor (Tr) is coupled. The diode (D10) allows a decreased resistor (R11) value which causes the supply voltage ripple (Vr1) on the collector originating from the base to decrease so as to better compensate the supply ripple (Vr2) on the collector directly originating from the supply voltage (Vs.).