6-6
Agilent Technologies E5500 Phase Noise Measurement System
Absolute Measurement Fundamentals
What Sets the Measurement Noise Floor?
What Sets the Measurement Noise Floor?
The noise floor for your measurement will be set by two things:
•
The noise floor of the phase detector and low-noise amplifier (LNA)
•
The noise level of the reference source you are using
The System Noise
Floor
The noise floor of the system is directly related to the amplitude of the input
signal at the R input port of the system’s phase detector.
The following table shows the amplitude ranges for the L and R ports.
If the L port (reference input) signal is within the amplitude range shown in
the preceding table, the signal level at the R (signal ) input port sets the noise
floor for the system.
The following graph shows the relationship between the R (signal) input
level and the system noise floor.
Phase Detector
50 kHz to 1.6 GHz
1.2 to 26.5 GHz
1
50 kHz to 26.5 GHz
2
Ref Input (L Port)
Signal Input (R
Port)
Ref Input (L Port)
Signal Input (R
Port)
AM Noise
+
15 dBm
to
+
23 dBM
0 dBm
to
+
23 dBM
+
7 dBm
to
+
10 dBM
0 dBm
to
+
5 dBM
0 dBm
to
20 dBM
1. Agilent/HP 70420A phase noise test set Options 001 and 201with no attenuation
2. Agilent/HP 70420A phase noise test set Option 001 with no attenuation
