The disclosed embodiments relate to a digital radio frequency (RF) circuit
that creates a signal in a desired range in a frequency spectrum. The RF
circuit comprises circuitry that produces a first sample data modulated
signal having a first frequency and a first sample data clock rate. An
up-sampler modulator receives the first sample data modulated signal and
produces a second sample data modulated signal having a second frequency
and a second sample data clock rate. The RF circuit may also comprise
circuitry that receives the first sample data modulated signal and the
second sample data modulated signal and delivers one of the first sample
data modulated signal and the second sample data modulated signal for
further processing depending on which sample data modulated signal
exhibits desirable characteristics for a given operating environment.