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Agilent E5505A User’s Guide
7
Residual Measurement Fundamentals
What is Residual Noise?
Residual or two-port noise is the noise added to a signal when the signal is
processed by a two-port device. Such devices include amplifiers, dividers,
filters, mixers, multipliers, phase-locked loop synthesizers or any other
two-port electronic networks. Residual noise is composed of both AM and FM
components.
The noise mechanisms
Residual noise is the sum of two basic noise mechanisms:
•
additive noise
•
multiplicative noise
Additive noise
Additive noise is the noise generated by the two-port device at or near the
signal frequency which adds in a linear fashion to the signal. See
Multiplicative noise
This noise has two known causes. The first, is an intrinsic, direct, phase
modulation with a 1/f spectral density and the exact origin of this noise
component is unknown. The second, in the case of amplifiers or multipliers, is
noise which may modulate an RF signal by the multiplication of baseband
noise with the signal. This mixing is due to any non-linearities in the two-port
network. The baseband noise may be produced by the active device(s) of the
internal network, or may come from low-frequency noise on the signal or
power supply. See
.
Figure 144
Additive noise components
Device under
test
E5505a_add_noise_comp
27 Feb 04 rev 1
Source
Noiseless
source
RF noise around
the signal frequency
RF noise added
to the signal
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 ...