| 摘要 |
PURPOSE:To obtain the output of a fluxmeter with a simple construction as resisting to externally induced noises and those noises due to the vibration and bending of an optical fiber, by transmitting a feedback signal on a PWM modulation light signal to separate a reference frequency from the light signal. CONSTITUTION:A SQUID signal modulated by a reference signal of a frequency f2 is transmitted to a controller II from a cryostat section I after converted into light from electricity and synchronously detected 20 after the light-electricity conversion to provide the output of a fluxmeter through an integrator 21. The output of the integrator 21 is modulated with a PWM circuit 23 as fixed to the same frequency and phase as the reference signal and converted into light from electricity as PWM signal corresponding to the output of the integrator 21 to be transmitted to the cryostat section I. After the optoelectric conversion, the output is separated 8 and 9 into a low frequency signal and a clock signal of a frequency f2 to be applied to a resonance circuit 13 as feedback signals and a reference signal. A circuit 9 triggers a monostable multivibrator at the rising of the PWM signal with a fixed phase to generate a square wave and then, a signal is obtained with an integration circuit as triangular signal completely fully synchronizing the reference signal. |
