Agilent Technologies E1420B, Руководство пользователя

Страница: 220 / 476

220 Agilent E5505A User’s Guide
7
Residual Measurement Fundamentals
3
Using the RF spectrum analyzer or modulation analyzer, measure the
carrier-to-sideband ratio of the phase modulation at the phase detector’s
modulated port and the modulation frequency. The audio calibration
source should be adjusted such that the sidebands are between –30 and
–60 dB below the carrier and the audio frequency is between 50 Hz and 50
MHz. See
Figure 158 .
4 Measure the carrier-to-sideband ratio of the non-modulated side of the
phase detector. It must be at least 20 dB less than the modulation level of
the modulated port. This level is necessary to prevent cancellation of the
modulation in the phase detector. Cancellation would result in a smaller
phase detector constant, or a measured noise level that is worse than the
Table 34 Acceptable amplitude ranges for the phase detectors
Phase Detector
50 kHz to 1.6 GHz 1.2 to 26.5 GHz
1
1 Phase noise test set options 001 and 201
Ref Input (L Port) Signal Input (R Port) Ref Input (L Port) Signal Input (R Port)
+
15 dBm
to
+
23 dBm
0 dBm
to
+
23 dBm
+
7 dBm
to
+
10 dBm
0 dBm
to
+
5 dBm
Figure 158 Measuring carrier-to-sideband ratio of the modulated port
Power
splitter Phase
detector
Source
Audio
calibration
source
-10 dB
attenuator
E5505a_meas_ratio_mod_port
01 Mar 04 rev 1
Optional line
stretcher
Phase
modulator
Test set
Signal
input
Ref input
10 kHz
- 40 dBc
RF spectrum
analyzer
}