Patent ID: 7084676

Claim:
Apparatus for direct digital generation of a synthesized RF output signal at a desired output frequency comprising: a high speed reference clock providing in an input signal having a series of signal reference edges at a frequency of the reference clock which is higher than the desired output frequency; programmable digital delay elements arranged to receive the reference edges of the input reference clock and to generate delayed signal edges each at a calculated delay from a respective reference edge; and a signal generating element for receiving the delayed signal edges and for generating the RF output signal therefrom; wherein the signal generating element is arranged to directly generate the RF output signal so as to comprise a series of pulses each having a rising edge and a falling edge; and wherein the signal generating element is arranged to generate the rising and a falling edges of the pulses at a digital timing determined by the delayed signal edges calculated from a respective reference edge; wherein the programmable digital delay elements comprise high speed adders/accumulators wherein said adders/accumulators are arranged to determine the amount of delay implemented by the delay elements on the reference edge.