Rather, it is sent to the input of a pulse-width modulator, which operates at a
free-running frequency many times greater than the highest frequency in the input waveform.
It is assumed that the VCO is modeled as a linear device whose output frequency deviates from its
free-running frequency by an increment of frequency[12] such that
Dielectric resonator oscillators (DRO) are highly stable fundamental oscillators in the 3 to 30 GHz region, achieving
free-running frequency stability of less than 1 ppm/[degrees] C in many eases.
The first method is to set the
free-running frequency to a desired center frequency and tune the low power coil current in a negative and positive direction to achieve [+ or -]1000 MHz tuning.
Here the local oscillator, typically operating in the mm-wave range, is synchronized to a pilot reference signal operating near the
free-running frequency of the oscillator, or to a pilot carrier that is parametrically related to the frequency reference by means of the nonlinear characteristics of a device in series with the oscillator.
The
free-running frequency of the oscillator is set by the distance between the Q-R band interface, which can be adjusted by spacer 1.