lu82562ex Intel Corporation, lu82562ex Datasheet - Page 61

• Manufacturer Part Number: lu82562ex
• Description: Dual Footprint
• Manufacturer: Intel Corporation

A.4
Example 1.
Indirect Frequency Measurement and Frequency Accuracy
Calculation Steps
1. Make sure the system BIOS has the LAN controller enabled.
2. Connect the test equipment as shown in
3. Using the appropriate controls for your model of high resolution digital counter, make sure it
4. Enable the 125 MHz buffered reference clock. An example can be found in
5. Determine the center reference frequency as accurately as possible. This can be done by taking
6. Calculate the accuracy of the measured and averaged center frequency with respect to an ideal
can display ~125.0000 MHz with at least four decimal places frequency resolution.
“GigConf.exe Register Settings for 82547GI(EI)
30 to 50 different readings using the frequency counter and then calculating the average results
of the readings.
125.0000 MHz reference frequency.
where
Given: The measured averaged center frequency is 124.99942 MHz (or 124,999,420 Hertz).
FrequencyAccuracy ppm
x = Average measured frequency in Hertz and
y = Ideal reference frequency in Hertz
FrequencyAccuracy ppm
(
)
82562EZ(EX)/82547GI(EI) Dual Footprint Design Guide
=
Figure
(
----------------------------------------------------------------
124999420 125000000
(
125000000 1000000
(
11.
Devices”.
)
=
–
------------------------------- -
(
y 1000000
⁄
⁄
(
x y
–
)
)
)
)
=
Appendix B,
–
4.64ppm
53