240 N5511A Phase Noise Test System User’s Guide
FM Discriminator Measurement Examples
FM Discriminator Single Channel Measurement using FM Rate and Deviation
Calibration
FM Discriminator Single Channel Measurement using FM Rate and
Deviation Calibration
Required Equipment
shows equipment required for this example in addition to the phase
noise test system and your DUT.
Determining the discriminator (delay line) length
Perform the following steps to determine the minimum delay line length (
τ
)
possible to provide an adequate noise to measure the source.
1.
Determine the delay necessary to provide a discriminator noise floor that
is below the expected noise level of the DUT.
floor of the discriminator for given delay times (t).
2.
Determine the length of coax required to provide the necessary delay (
τ
).
(Eight feet of BNC cable will provide 12 ns of delay for this example.)
3.
Determine the loss in the delay line. Verify that the signal source will be
able to provide a power level at the output of the delay line of b5
and +17 ICBM. Be sure to take into account an additional 4 to 6 dB of loss
To prevent damage to the test set’s components,
do not
apply a signal beyond the systems
specifications. Refer to the data sheet for power specifications.
In order to use the FM rate and deviation calibration method you must have a signal source that is
calibrated for FM modulation rate and FM deviation parameters. All Keysight Technologies signal
generators meet this requirement.
To ensure accurate measurements allow the DUT and measurement equipment to warm up at
least 30 minutes before making the noise measurement.
Table 10-3
Required Equipment for the FM Discriminator
Measurement Example
Equipment
Quantity
Comments
Signal Generator
1
+19 dBm output level at tested carrier frequency.
Calibrated FM at a 20 kHz rate with 10 kHz Peak
Deviation.
Power Splitter
1
NARDA 30183
Delay Line
Delay (or length) adequate to decorrelate source noise.
Phase Shifter
1
±180° phase shifter at lowest carrier frequency tested.
Summary of Contents for N5511A
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