| 摘要 |
PROBLEM TO BE SOLVED: To reduce fluctuation in an oscillation frequency due to dispersion in a temperature characteristic of a dielectric resonator in a local oscillation circuit such as an LNB using the dielectric resonator. SOLUTION: A temperature compensation circuit 6a is provided between a drain (D) terminal of an oscillation FET and a DC power supply Vo, a drain- source voltage of the FET is changed in response to fluctuation in ambient temperature to compensate the fluctuation in the oscillated frequency. This temperature compensation circuit 6a is applied when the frequency gets higher as a temperature characteristic of the dielectric resonator is increasing. The temperature compensation circuit 6a uses a thermister Rta to decrease a drain voltage Vd when ambient temperature rises resulting in decreasing the oscillating frequency, and to increase the drain voltage when ambient temperature falls resulting in increasing the oscillating frequency.
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