
Extending the VCO Tuning Voltage Range value as denned on the Instru-
ment Parameters display to 10V is a valid way to increase the Peak Tun-
ing Range for the measurement. The VCO source being used in this case
must be a signal generator with a calibrated DC FM Input (such as the
HP 8662A). When the tuning range has been extended, select the "Com-
pute from Expected T. Constant" calibration method for the measurement.
Refer to the "Enhanced Tuning Range" description in Instrument Param-
eters in this chapter for complete details on extending the VCO Voltage
Tuning Range.
Compute from Expected T. Constant
Selecting the Compute from Expected Tuning Constant method causes
the system to use the entered VCO Tuning Constant and Tune-port Input
Resistance that have been defined on the Instrument Parameter display.
This method requires that the entered VCO Tuning Constant is within
±5%
of the VCO's actual sensitivity. If it is not, the system will report an
Accuracy Specification Degradation after verifying the Phase Lock Loop
Suppression.
p.
VCO Tuning Constant
—
Entered VCO Tuning Constant x
Where : R{
n
= VCO Tune Port Input Resistance
2-52 Calibr Process: $N w/PLL
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