User`s guide

Table Of Contents
298 Agilent E5505A User’s Guide
11
AM Noise Measurement Fundamentals
Method 2, example 2
Advantages
Will measure source without modulation capability
Calibration is done under actual measurement conditions so all
non-linearities and harmonics of the AM detector are calibrated out. The
double-sided spur method and the single-sided-spur method are the two
most accurate methods for this reason.
Disadvantages
Requires a second RF source with very accurate AM modulation and output
power sufficient to match the DUT. If the AM modulation is not very
accurate, a modulation analyzer must be used to make manual
measurement of the AM sidebands.
Procedure
1
Connect circuit as shown in Figure 230, and tighten all connections. If the
N5500A Option 001 or N5507A is available, use one of the connection
diagrams described in “AM noise measurement block diagrams" on
page 287.
2
Measure the power which will be applied to the AM detector (Figure 231). It
must be between 0 and +23 dBm.
3
Using a source with AM, set its output power equal to the power measured
in step 2. The source should be adjusted such that the sidebands are
Figure 230 Double-sided spur AM noise setup (method 2, example 2)
Figure 231 Measuring power at the am detector
DUT
Power meter
or RF spectrum
analyzer