| 摘要 |
PURPOSE:To take a measurement with low noise and to phase difference by shifting the phase of the output signal of an oscillation circuit and eliminating the phase difference from a filter circuit. CONSTITUTION:When a phase difference is generated between the output of the oscillation circuit 1 and the filter 9, a phase difference detecting circuit 3 detects the phase difference between the output of the circuit 1 and the output of the filter 9 and inputs a phase difference signal to a transporting circuit 4. The circuit 4 shifts the output signal from the circuit 1 according to the phase difference signal so that the phase difference between the output of the circuit 1 and the filter 9 becomes zero, and outputs the signal to a V/I converting circuit 5. Then the phase difference between the output of the circuit 1 and the filter 9 is eliminated and the current-voltage characteristic and magnetic flux-voltage characteristic of DC-SQUID 6 can be measured. Consequently, the generated phase difference can be corrected automatically, so the measurement is performed with low noise and no phase difference at all times. |
