When not in use, the unit can be disconnected from the meter, the ribbon cable tucked under the lid of the meter and the meter used in its standard mode. If the meter is properly insulated from air temperature changes, the digital system makes a fine earth tide recording system. L and R is pleased to provide advice on the application and has computer programs available for processing and analysis of the data. A power supply and clock are required for the digital nuller. They may be provided by the user.
Many observatories have an accurate source of one second time pulses.
One is supplied by 115 or 230 VAC power, provides the regulated DC voltages need by the nuller and has a dividing circuit for obtaining one second pulses from the 50 Hertz or 60 Hertz AC power. If the AC power source has frequent interruptions or does not have good long term timing accuracy, the 12 VDC unit is the preferable unit. The manual for this option has more detailed information. Feedback System was designed in 1989 by Dr. Michel van Ruymbeke of the Royal Observatory of Belgium. It has been installed on more than 30 L and R meters.