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Agilent E5505A User’s Guide
5
Absolute Measurement Fundamentals
Evaluating Noise Above the Small Angle Line
If the average noise level on the input signals exceeds approximately 0.1
radians RMS integrated outside of the Phase Lock Loop (PLL) bandwidth, it
can prevent the system from attaining phase lock.
The following procedure allows you to evaluate the beatnote created between
the two sources being measured. The intent is to verify that the PLL
bandwidth is adequate to prevent the noise on the two sources from causing
the system to lose lock.
If the computer is displaying the hardware Connect Diagram you are ready to
begin this procedure. (If it is not, begin a New Measurement and proceed until
the hardware Connect Diagram appears on the display.)
Determining the Phase-Lock-Loop bandwidth
1
Determine the Peak Tuning Range (PTR) of your VCO by multiplying the
VCO Tuning Constant by the Tune Range of VCO value entered. (If the
phase noise software has measured the VCO Tuning Constant, use the
measured value.)
For Example:
2
Estimate the Phase Lock Loop (PLL) bandwidth for the measurement using
the PTR of your VCO and the graph in
Observing the beatnote
If the beatnote frequency is below 100 kHz it appears on the Agilent E4411A
RF analyzer’s display in both the frequency domain and the time domain. If
the beatnote does not appear on the RF analyzer, then the beatnote is either
greater than 100 kHz or it does not exist.
If incrementing the frequency of one of the sources does not produce a
beatnote within 100 kHz, you need to verify the presence of an output signal
from each source before proceeding.
Tuning
Voltage
X
Constant
Tuning
VCO
PTR
=
kHz
V
X
V
Hz
PTR
1
10
100
=
=
Summary of Contents for E1420B
Page 24: ...24 Agilent E5505A User s Guide ...
Page 46: ...46 Agilent E5505A User s Guide 2 Introduction and Measurement ...
Page 128: ...128 Agilent E5505A User s Guide 5 Absolute Measurement Fundamentals ...
Page 226: ...226 Agilent E5505A User s Guide 7 Residual Measurement Fundamentals ...
Page 322: ...322 Agilent E5505A User s Guide 13 Baseband Noise Measurement Examples ...
Page 340: ...340 Agilent E5505A User s Guide 14 Evaluating Your Measurement Results ...
Page 358: ...358 Agilent E5505A User s Guide 15 Advanced Software Features ...
Page 386: ...386 Agilent E5505A User s Guide 16 Reference Graphs and Tables ...
Page 392: ...392 Agilent E5505A User s Guide 17 System Specifications ...
Page 404: ...404 Agilent E5505A User s Guide 18 System Interconnections ...
Page 452: ...452 Agilent E5505A User s Guide 20 PC Digitizer Performance Verification ...
Page 466: ...466 Agilent E5505A User s Guide 21 Preventive Maintenance ...