GPS Disciplined Oscillator (GPSDO) 50Hz for Flip-Clock
Have you ever been annoyed by the fact that the accuracy of your flip-clock highly depends on the stability of your power grid frequency. Unfortunately, this frequency can vary significantly during the day. If the frequency is above the nominal value the flip-clock will be ahead of the actual time. If the frequency is below, the flip-clock will be behind. Not all countries have to maintain the network frequency constant. In such countries, the time error will be accumulated, and the time displayed on your flip-clock will be incorrect.
Another annoying problem, if you move to a country with a different power grid frequency than your flip-clock requires, you can just say good-bye to your flip-clock.
I have developed a GPSDO 50 Hz for widely spread COPAL motors. It eliminates the dependence of the flip-clock on the grid frequency and increases its accuracy to the level of an atomic clock. How does it work?
The AC mains voltage is first converted to DC, which is then being converted to a stable frequency of 50Hz by an ATMega328P microcontroller. The frequency is disciplined by the microcontroller using GPS signals (1PPS + current time).
Based on this 50Hz GPSDO, I assembled my first GPS Disciplined Copal Flip-Clock. (see the photos) The GPS disciplined flip-clock has an LED Status Indicator, Start/Stop & Alarm ON/OFF switch.
The LED status indicator shows the operation mode:
Green. Disciplined mode. Stable GPS signal is being received and GPSDO frequency is being tightly kept at 50Hz. The flip-clock has the best accuracy, almost comparable to an atomic clock.
Red. Free running mode. If by any reason GPS signal is not present, the red LED lights up. In this case there is no frequency stabilization. The flip-clock continues to run, but it now fully relies on internal quartz accuracy only.
Blue. Compensation mode. When the GPS signal is back, the flip-clock time readings are compared to the GPS time. In case of a mismatch greater than 20ms the blue LED lights up. The frequency is then either reduced to 49Hz or increased to 51Hz. The compensation mode is active until the flip-clock time matches with the GPS time. As soon as this happens, the frequency is set back to 50Hz and the green LED turns on. The flip-clock goes back into disciplined mode.
Have you ever been annoyed by the fact that the accuracy of your flip-clock highly depends on the stability of your power grid frequency. Unfortunately, this frequency can vary significantly during the day. If the frequency is above the nominal value the flip-clock will be ahead of the actual time. If the frequency is below, the flip-clock will be behind. Not all countries have to maintain the network frequency constant. In such countries, the time error will be accumulated, and the time displayed on your flip-clock will be incorrect.
Another annoying problem, if you move to a country with a different power grid frequency than your flip-clock requires, you can just say good-bye to your flip-clock.
I have developed a GPSDO 50 Hz for widely spread COPAL motors. It eliminates the dependence of the flip-clock on the grid frequency and increases its accuracy to the level of an atomic clock. How does it work?
The AC mains voltage is first converted to DC, which is then being converted to a stable frequency of 50Hz by an ATMega328P microcontroller. The frequency is disciplined by the microcontroller using GPS signals (1PPS + current time).
Based on this 50Hz GPSDO, I assembled my first GPS Disciplined Copal Flip-Clock. (see the photos) The GPS disciplined flip-clock has an LED Status Indicator, Start/Stop & Alarm ON/OFF switch.
The LED status indicator shows the operation mode:
Green. Disciplined mode. Stable GPS signal is being received and GPSDO frequency is being tightly kept at 50Hz. The flip-clock has the best accuracy, almost comparable to an atomic clock.
Red. Free running mode. If by any reason GPS signal is not present, the red LED lights up. In this case there is no frequency stabilization. The flip-clock continues to run, but it now fully relies on internal quartz accuracy only.
Blue. Compensation mode. When the GPS signal is back, the flip-clock time readings are compared to the GPS time. In case of a mismatch greater than 20ms the blue LED lights up. The frequency is then either reduced to 49Hz or increased to 51Hz. The compensation mode is active until the flip-clock time matches with the GPS time. As soon as this happens, the frequency is set back to 50Hz and the green LED turns on. The flip-clock goes back into disciplined mode.
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