Test Descriptions
10 MHz Out Frequency Reference Accuracy
10 MHz Out Frequency Reference Accuracy
Test Description
The test applies to NFAs with either the standard 10 MHz frequency reference or 10
MHz precision frequency reference (Option 1D5).
The test measures both the frequency reference accuracy and the ability to set the
timebase. The frequency reference accuracy is measured with the NFA's 10 MHz
REF OUT connected to the frequency counter's Channel A input. A cesium beam
frequency standard, or some other 10 MHz ± "house standard" provides the
frequency reference for the frequency counter. The timebase to be set is measured
by changing the setting of the digital-to-analog converter (DAC) which controls the
frequency of the timebase. The frequency difference over the range of DAC settings
is calculated and compared to the specification.
Test Specification
Ageing Rate
Settability
Temperature Stability
Related Adjustment
10 MHz Frequency Reference Adjustment (see page 20).
14
Standard
< ±2 ppm/year
< ±0.5 ppm
< ±6 ppm
Option 1D5
< ±0.1 ppm/year
< ±0.01 ppm
< ±0.01 ppm
Chapter 2