| 摘要 |
PURPOSE: A secondary voltage controlling oscillator for a double conversion typed tuner is provided to use a pattern condenser and a pattern coil in an oscillation tank circuit and prevent a deviation occurrence and an unstableness of an oscillation frequency. CONSTITUTION: An oscillation tank circuit(100) is composed as a varactor(VD10), a pattern condenser(CP10), the first pattern coil(LP10), and the second pattern coil(LP20) for determining an oscillation frequency according to a tuning voltage(VT) inputted from the outside. A voltage stable unit(200) has dividing resistors(R10,R20) and a stability transistor(TR10) for uniformly maintaining a voltage(B+) inputted from a power terminal and providing the uniform voltage to an oscillation frequency generating unit(300). The oscillation frequency generating unit(300) has an oscillation transistor(TR20) to be operated according to a voltage provided through the voltage stable unit(200) and be oscillated by an oscillation signal outputted from the oscillation tank circuit(100), dividing resistors(R30,R40) to be interconnected with a base of the oscillation transistor(TR20) in parallel for dividing the voltage, a resistor(R50) to be connected with an emitter of the oscillation transistor(TR20) for adjusting a feedback voltage of the oscillation tank circuit(100), and condensers(C20,C30) for adjusting a frequency.
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