Fm Discriminator Single Channel Measurement Using Fm Rate And Deviation Calibration; Required Equipment; Determining The Discriminator (Delay Line) Length - Keysight Technologies N5511A User Manual

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
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.

Required Equipment

Table 10-3
noise test system and your DUT.
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
Equipment
Signal Generator
Power Splitter
Delay Line
Phase Shifter

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
2. Determine the length of coax required to provide the necessary delay (τ).
3. Determine the loss in the delay line. Verify that the signal source will be
240
shows equipment required for this example in addition to the phase
Required Equipment for the FM Discriminator
Measurement Example
Quantity
1
1
1
is below the expected noise level of the DUT.
floor of the discriminator for given delay times (t).
(Eight feet of BNC cable will provide 12 ns of delay for this example.)
able to provide a power level at the output of the delay line of between +5
and +17 ICBM. Be sure to take into account an additional 4 to 6 dB of loss
Comments
+19 dBm output level at tested carrier frequency.
Calibrated FM at a 20 kHz rate with 10 kHz Peak
Deviation.
NARDA 30183
Delay (or length) adequate to decorrelate source noise.
±180° phase shifter at lowest carrier frequency tested.
Figure 10-11
N5511A Phase Noise Test System User's Guide
shows the noise