18-8
Agilent Technologies E5500 Phase Noise Measurement System
Reference Graphs and Tables
Voltage Controlled Source Tuning Requirements
Voltage Controlled Source Tuning Requirements
Peak Tuning Range (PTR)
≈
Tune Range of VCO x VCO Tune Constant.
Min. PTR =.1 Hz
Max. PTR = Up to (200 MHz depending on analyzer and phase detector
LPF).
Drift Tracking Range = Allowable Drift During Measurement.
The tuning range that the software actually uses to maintain quadrature is
limited to a fraction of the peak tuning range (PTR) to ensure the tuning
slope is well behaved and the VCO Tune Constant remains accurate. After
phase lock is established, the test system monitors the tuning voltage
required to maintain lock. If the tuning voltage exceeds 5% of the PTR
during the measurement, the test system again informs the user and requests
the oscillator be retuned or the problem be otherwise corrected before
proceeding with the measurement. These limits have been found to
guarantee good results.