Patent attributes
A frequency-agile frequency source. The frequency source includes an oscillator having an output and being configured to generate a signal at a first frequency at the output, a first direct digital synthesizer (DDS) having an output and a sampling clock input connected to the output of the oscillator, a filter amplifier block having an input directly connected to the output of the first DDS and an output, and a second DDS having a sampling clock input directly connected to the output of the filter amplifier block. The filter amplifier block is a substantially linear time-invariant element having a frequency response, the magnitude of the frequency response being at least 12 dB lower, at a second frequency within the first Nyquist zone of the first frequency, than at a third frequency above the first Nyquist zone of the first frequency.
