Agilent Technologies E5500 Phase Noise Measurement System
6-11
Absolute Measurement Fundamentals
Estimating the Tuning Constant
Estimating the Tuning Constant
The VCO tuning constant is the tuning sensitivity of the VCO source in
Hz/V. The required accuracy of the entered tuning constant value depends
on the VCO tuning constant calibration method specified for the
measurement. The calibration method is selected in the Calibr Process menu.
The following chart lists the calibration method choices and the tuning
constant accuracy required for each.
Table 6-2
VCO Tuning Constant Calibration Method
VCO Tuning Constant Calibration
Method (selected in calibration
screen)
Required Tuning Constant
Accuracy (entered in parameter
screen)
Use the current tuning constant
(must be accurate from a previous
measurement of the same source).
Within a factor of 2 of actual value.
(Enter 1 E + 6 for Input
Resistance.)
Measure the VCO tuning constant
Within a factor of 2 of actual value.
(Enter 1 E + 6 for Input
Resistance.)
Calculate from expected T. Constant
Exact, within 5% of actual.
(Also requires that entered Input
Resistance value is accurate.)
