| 摘要 |
<p>A local oscillation apparatus employing a dielectric coaxial resonator (27) which is used as a fixed local oscillation circuit for a tuner of the double super system and for a converter for CATV; wherein the center conductor of the dielectric coaxial resonator (27) is connected to an end of a variable-capacity diode (23) via a capacity (25), the other end of the diode being grounded in an AC manner, an AFC voltage being applied from an output terminal (E) of a frequency control circuit to the variable-capacity diode (23) via a resistor (35), and a first reference potential (VA) which is smaller than the power source voltage (VCC) by a predetermined potential drop being also applied thereto; wherein one end of the variable-capacity diode (23) is connected to the power source voltage (VCC) via a second resistor (22); and wherein even when the power source voltage (VCC) undergoes the change, the voltage does not change across both terminals of the variable-capacity diode (23) to prevent the oscillation frequency from changing.</p> |
