Direct frequency synthesizer using powers of two synthesis techniques

A signal generator for producing an output signal having an output frequency determined by a digital control word, the signal generator comprising:

• means for producing a plurality of sets of reference signals, each set having a plurality of reference signals each having a reference frequency differentiated from reference frequencies of other reference signals in the set by a multiple of an integral power of two;
• a plurality of means for selecting, each receiving one or more bits of the digital control word and the reference signals from one set for selecting according to the digital control word one reference signal from each set as a selected signal having a selected frequency;
• and
• means responsive to the selected signals for mathematically combining the selected frequencies of the selected signals to produce the output signal having the output frequency which is a mathematical combination of the selected frequencies of each selected signal, wherein a binary offset word is added to said digital control word to cause the output signal to have a desired frequency.

A signal generator for producing an output signal having an output frequency determined by a digital control word, the signal generator comprising:

• means for producing a plurality of sets of reference signals, each set having a plurality of reference signals each having a reference frequency differentiated from reference frequencies of other reference signals in the set by a multiple of an integral power of two;
• a plurality of means for selecting, each receiving one or more bits of the digital control word and the reference signals from one set for selecting according to the digital control word one reference signal from each set as a selected signal having a selected frequency;
• and
• means responsive to the selected signals for mathematically combining the selected frequencies of the selected signals to produce the output signal having the output frequency which is a mathematical combination of the selected frequencies of each selected signal;
• wherein the relative phases of the various reference signals are unaffected by any selections made by the means for selecting, whereby the output signal maintains phase memory when said output signal is adjusted from a first frequency, to one or more frequencies other than said first frequency, and is returned to said first frequency.

A signal generator for producing an output signal having an output frequency determined by a digital control word, the signal generator comprising:

• means for producing a plurality of sets of reference signals, each set having a plurality of reference signals each having a reference frequency differentiated from reference frequencies of other reference signals in the set;
• a plurality of means for selecting, each receiving one or more selected bits of the digital control word and the reference signals from one set for selecting according to the digital control word one reference signal from each set as a selected signal having a selected frequency;
• and
• means responsive to the selected signals for mathematically combining the selected frequencies of the selected signals to produce the output signal having the output frequency which is a mathematical combination of the selected frequencies of each selected signal, wherein application of selected bits to said means for selecting is delayed by a time unique to each said means for selecting, such that any changes in selection of reference signals caused by a change in the control word have simultaneous effect on said output signal.

A signal generator for producing an output signal having an output frequency determined by a digital control word, the signal generator comprising:

• means for producing a plurality of sets of reference signals, each set having a plurality of reference signals each having a reference frequency differentiated from reference frequencies of other reference signals in the set;
• a plurality of means for selecting, each receiving one or more bits of the digital control word and the reference signals from one set for selecting according to the digital control word one reference signal from each set as a selected signal having a selected frequency;
• and
• means responsive to the selected signals for mathematically combining the selected frequencies of the selected signals to produce the output signal having the output frequency which is a mathematical combination of the selected frequencies of each selected signal, wherein a binary offset word is added to said digital control word to cause the output signal to have a desired frequency.

A signal generator for producing an output signal having an output frequency determined by a digital control word, the signal generator comprising:

• means for producing a plurality of sets of reference signals, each set having a plurality of reference signals each having a reference frequency differentiated from reference frequencies of other reference signals in the set;
• a plurality of means for selecting, each receiving one or more bits of the digital control word and the reference signals from one set for selecting according to the digital control word one reference signal from each set as a selected signal having a selected frequency;
• and
• means responsive to the selected signals for mathematically combining the selected frequencies of the selected signals to produce the output signal having the output frequency which is a mathematical combination of the selected frequencies of each selected signal;
• wherein the relative phases of the various reference signals are unaffected by any selections made by the means for selecting, whereby the output signal maintains phase memory when said output signal is adjusted from a first frequency, to one or more frequencies other than said first frequency, and is returned to said first frequency.