Patent ID: 7209936

Claim:
A digitally tuned synthesizer comprising: a) a register for receiving a digital word having a predetermined number of bits; b) a partitioner interconnected to said register for partitioning said predetermined number of bits of said digital word into coarse and fine control words; c) a first digital to analog converter connected to said coarse control word and providing an output representative of said coarse control word; d) a combiner having first and second inputs receiving signals and an output representative of the sum of the signals received on the first and second inputs, said first input connected to said output of said first digital to analog converter; e) at least one voltage controlled oscillator having a first input connected to said output of said combiner and providing a RF output having a first and a second band and representative of its first and second input; f) a coupler connected to said RF output having said first band and providing a representative output signal thereof; g) a sampling downconverter having first and second inputs with the first input connected to said output of said coupler and the second input connected to received at least one sampling signals consisting of at least one clock signal, said sampling downconverter providing a beat frequency output signal resulting from the mixing of the signals connected to the first and second inputs of said sampling downconverter; h) a frequency measurement circuit connected to the output of said sampling downconverter and providing an output representative thereof; i) a first adder having plus (+) and minus (−) inputs, said plus (+) input being connected to said fine control word, said minus (−) input being connected to said output of said frequency measuring circuit, said first adder having an output representative of the difference between its inputs; and j) a second digital to analog converter connected to said output of said first adder and providing an output representative thereof that is connected to said second input of said combiner.