Frequency synthesizer using divided and frequency converted DDS signal as reference for PLL

A method for synthesizing a final signal having a predetermined frequency comprising steps of:

• generating an oscillating signal having an oscillating frequency by a direct digital synthesizer;
• dividing the oscillating frequency to provide a divided signal having a divided frequency;
• converting the divided frequency to provide a converted signal;
• and
• inputting the converted signal into a phase locked loop as a reference signal for generating the final signal.

A frequency synthesizer for generating a final signal having a predetermined frequency characteristic, the frequency synthesizer comprising:

• a direct digital synthesizer for generating a first signal having a first frequency characteristic determined by first channel setting data and having a first amplitude;
• a first divider, operatively connected to the direct digital synthesizer, for dividing the first frequency characteristic of the first signal to generate a divided signal having a divided frequency characteristic;
• a frequency converter, operatively connected to the first divider, for shifting the divided frequency characteristic by a shift frequency interval to provide a reference signal having a reference frequency characteristic;
• and
• a phase locked loop for generating the final signal from the reference signal.

A method for synthesizing a final signal having a predetermined frequency characteristic, the method comprising the steps of:

• A. generating a first signal, having a first frequency characteristic determined by first channel setting data and having a first amplitude, at a direct digital synthesizer;
• B. dividing the first frequency characteristic of the first signal to generate a divided signal having a divided frequency characteristic;
• C. shifting the divided frequency characteristic by a shift frequency interval to provide a reference signal having a reference frequency characteristic;
• and
• D. generating the final signal from the reference signal, at a phase locked loop.

A frequency synthesizer for generating a final signal having a predetermined frequency characteristic, the frequency synthesizer comprising:

• a means for generating a first signal having a first frequency characteristic by digital operations and determined by first channel setting data;
• a first divider, operatively connected to the means for generating, for dividing the first frequency characteristic of the first signal to generate a divided signal having a divided frequency characteristic;
• a frequency converter, operatively connected to the first divider, for shifting the divided frequency characteristic by a shift frequency interval to provide a reference signal having a reference frequency characteristic;
• and
• a phase locked loop for generating the final signal from the reference signal.