| 摘要 |
<p>A superconducting filter device comprises a superconducting filter having a predetermined pass-band characteristic when cooled to cryogenic temperature; a freezer for cooling the superconducting filter to cryogenic temperature; a pilot signal generator that generates a pilot signal out of the pass band and supplies the superconducting filter with the pilot signal together with a signal received through antenna; and means for detecting trouble with the freezer. If the temperature of the superconducting filter rises because of trouble with the freezer, the pass band of the superconducting filter shifts to the low-frequency side and overlaps the pilot signal frequency, thus allowing the pilot signal to pass through the superconducting filter. The means for detecting trouble with the freezer makes a decision depending on the pilot signal included in the output from the superconducting filter.</p> |
