(Goal of R&D is to move technologies toward the upper left)
7-2
* Accuracy vs, size, and accuracy vs. cost have similar relationships
10-12
10-10
10-8
10-6
10-4
Text Box: Accuracy
Accuracy
Text Box: Power (W)
Power (W)
0.01
0.1
1
10
100
0.001
XO
TCXO
OCXO
Rb
Cs
1ms/day
1ms/year
1ms/day
1s/year
1s/day
Clock Accuracy vs. Power Requirement*
7-2
   Commercially available frequency sources cover an accuracy range of several orders of magnitude - from the simple XO to the cesium-beam frequency standard. As the accuracy increases, so does the power requirement, size, and cost.  Shown above is the relationship between accuracy and power requirement. (Note that it is a log-log scale.)  Accuracy versus cost would be a similar relationship, ranging from about $1 for a simple XO to about $40,000 for a cesium standard (1997 prices).