LC oscillators. The 8th publication. nanyoly mendez. EES Section 1. 3rd part



Atomic Clock with Crystal Oscillators

NASA's atomic clock

selected atoms (low energy) later passed through a focused microwave field produced by a transmitter that is controlled by a quartz crystal oscillator configured to vibrate 9,192,631,770 Hertz (or cycles) per second. The frequency of the microwave field is not always accurate and ranges with respect to the vibration required, but this variation is always minimal and at some point in each cycle ever get to reach the correct frequency.

An atom changes to a high energy state only if it passes through the microwave field at the time it reaches the correct frequency. These atoms, which have shifted their energy state, are later detected and controlled by a device at the end of the vacuum tube.

At that time, another magnetic field the atoms sorted and filtered to identify those with the proper energy state. If the number of these atoms does not reach a threshold level, this means that the crystal oscillator is not working properly so that it conforms to transmit the correct frequency. In a separate device, is then converted to the oscillation frequency pulses of exactly one second each.

The first atomic clock of history (the variation was of a second each 300 years). Compare with the wonders that today produces miniaturization (gains or delay one second every 10,000 years).

Nanyoly Mendez

Solid-State Electronics Section 1