Use of induced noise to calibrate injection-locked phase noise measurements

A new calibration approach is described for phase noise measurements of free-running voltage controlled oscillators using the injection locking technique. The injection locking technique allows the locking of free running oscillators to a reference over a wide bandwidth during a phase noise measurement. Compared to conventional phase noise measurement techniques, the injection locking technique involves a calibration procedure, which may be tedious and time consuming. The new approach may be used to perform an automated calibration procedure of the system commonly used for these measurements.