
Parameter Entry Descriptions
Use the Current Tuning Constant
This calibration method uses the value of the Tuning Constant currently in
memory. Selecting this method can save the time of measuring the Tuning
Constant without any degradation in accuracy, providing either the same
VCO source is being used or a source with an identical Tuning Constant
is being used (within ±5%).
Measure the VCO Tuning Constant
Selecting this calibration method causes the system to automatically
measure the tuning sensitivity and tuning linearity of the VCO source.
Measuring the Tuning Constant is the recommended method under most
circumstances for ensuring measurement accuracy. (As noted below, the
special case of extending the VCO Tuning Voltage Range requires selection
of the Compute from Expected T. Constant calibration method.) The
system cannot measure the Tuning Constant for an entered Peak Tuning
Range greater than 500 kHz for systems configured without an RF
Analyzer, and 200 MHz for systems configured with an RF Analyzer.
When measuring the VCO Tuning Constant, the system requires that the
VCO Tuning Constant defined in the Instrument Parameter display be
within a factor of two of the VCO's actual sensitivity. This approximation is
required in order for the HP 3048A to establish a beatnote. The frequency
response of the VCO source must remain flat (±.3 dB) from dc to the
phase lock loop bandwidth (PLL BW).
Calibr Process: $N w/PLL 2-51
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