A new system, in which a real-time VLBI (very-long-baseline interferometer) is utilized, for real-time monitoring of atmospheric disturbances on a very-long baseline has been developed. In this system, beacon waves from geo-stationary satellites are used for received signals and public communication lines are used for data transmission. Connecting the system to the 6-m Kagoshima and the 10-m Mizusawa radio telescopes enables atmospheric disturbances to be observed. The cross-correlation phase was calculated from the received signals, and the Allan standard deviation of the phase was obtained. It was found that the Allan standard deviation across almost the whole region of the time interval reflects atmospheric disturbances.

A switched-capacitor phase-shifter oscillator of low distortion is discussed. The dc voltage related to the amplitude of oscillation was made for an automatic gain controller. The distortion factor was less than 0.5% in the frequency range from 100 µHz to 1 Hz.

A switched-capacitor Wien bridge oscillator and its automatic gain controller are discussed for low-frequency generation. The dc voltage Vs related to the amplitude of oscillation is obtained from the voltage differences in the frequency-determining arm. Theoretical analysis of the ripples in Vs is reported.