LMK01000EVAL/NOPB National Semiconductor, LMK01000EVAL/NOPB Datasheet - Page 10

• Manufacturer Part Number: LMK01000EVAL/NOPB
• Description: BOARD EVALUATION FOR LMK01000
• Manufacturer: National Semiconductor

Specifications of LMK01000EVAL/NOPB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Noise Floor Measurements
Reason and Methodology
When measuring output noise, consideration should be taken to note the inherent noise of the input source in
order to accurately reflect the performance of the LMK01000. The measured output noise consists of the output
noise of the LMK01000 - plus the inherent noise of the signal generator, or reference signal input, chosen. To
determine the actual noise floor of the device, the input noise must be measured, or interpolated. The charts
referenced below were compiled with measurements from an Agilent E5052A Signal Source Analyzer.
This methodology can be visualized in the following formula expressions:
Measured Noise
The above expression can be solved for DeviceNoise as follows:
Three (3) samples are depicted to help further explain this methodology:
•
•
•
Raw Data chart – depicting an input of 245.76 MHz with no internal dividers affecting output
(
Smoothed Data chart – Raw data “smoothed” to help remove extraneous noise from the graphical
representation. (
Corrected Data chart – depicts an input of 245.76 MHz with no internal dividers affecting output.
Input noise (as measured above in the Raw data chart) removed and calculated actual noise floor
of device and outputs shown. (
See Chart #1
10
Device
(
MeasuredNo
Noise
)
ise
/
10
See Chart #2
=
)
=
10
10
⋅
log
(
DeviceNois
)
(
10
See Chart #3
Measured
e
/
10
)
+
Noise
10
/
)
(
10
SigGenNois
10
−
10
SigGen
e
/
10
)
Noise
/
10
)