Scope Clock and Nixie Tube Clock with Best Accuracy

Overview

The project shows a nixie clock that is accurate to a few nanoseconds a day while being synchronized with a cesium atomic clock.

Explanation

The nixie clock was originally synchronized with the 60Hz power line frequency but the new version includes an atomic frequency standard for driving the nixie clock. To generate a high voltage mains, the low level 60Hz sine wave signal generated by the synthesizer is amplified with a bipolar DC power supply.

The ‘scope clock is driven by the 1 PPS output of an Agilent 5071/001 Primary Frequency Standard or cesium atomic clock which provides the nanoseconds accuracy. A 1 PPS BNC input is located on the rear of the special ‘scope clock and allows the clock to be driven by a more accurate time source such as WWVB radio clock, a GPS satellite receiver, or an atomic clock.

The nixie tube clock is similar to desk clock, which derives its timekeeping from the 60Hz power line. A synthesizer was locked to the 5MHz output of the atomic standard to drive the nixie clock from an atomic frequency standard. The nixie clock is powered from synthesized mains.