Determining The Discriminator Delay Line) Length - Agilent Technologies E5500A User Manual

Determining the
Discriminator
(Delay Line) Length
Document Part No. E5500-90024Ed. 1.0
Discriminator Measurement using FM Rate and Deviation Calibration
Table 11-4 Required Equipment for the FM Discriminator Measurement
Example
Equipment
Delay Line
Phase Shifter
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.
shows the noise floor of the discriminator for given delay times
( τ ).
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 between +5 and +17 ICBM. Be sure to take into account an
additional 4 to 6 dB of loss in the power splitter. (The loss across
E5500 Phase Noise Measurement System Version A.02.00
FM Discriminator Measurement Examples
Quantity Comments
Delay (or length) adequate to
decorrelate source noise.
± °
1 180 phase shifter at lowest
carrier frequency tested.
11
Figure
11-21