Appendix C - Use of Common Instruments and Meters
Confidential and Proprietary Information of ZTE CORPORATION 221
F
I G U R E
1 0 4
3
D
B
B
A N D W I D T H O F
S
I G N A L
3dB
Band
width
x.
For two signals with near frequencies and very different
AMPLITUDEs, we call one of them as big signal and the other one
as small signal. To avoid that the small signal is submerged by the
big signal, set the big signal with 60DB bandwidth and small one
with 3DB bandwidth.
xi.
The judgment condition is: half of the 60DB bandwidth of the big
signal is not less than the frequency interval between two signals.
You also can use the method of setting “UP/LOW LIMIT LINE”
during the observation.
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I G U R E
1 0 5
I
L L U S T R A T I O N F O R
M
E T H O D O F
U P / L O W
L I M I T
L I N E
PASS
UP LINE
LOW LINE
SIGNAL
Make the signal to be tested into a template, and the spectrum
analyzer will judge whether the real-time signal meets the
requirement. If it meets the requirement, “PASS” will be displayed
on the upper right corner of the screen, otherwise, “FAIL” will be
displayed, indicating the tested signal does not meet the
requirement.
