n synthesizer to generate the needed waveforms can be used only with synthesizers that provide an internal phase frequency detector pfd that operates at frequencies equal to or above 110 mhz when using the fractional n synthesizers very small on the order of hz out of millions of hz frequency step sizes are used during the lfm generation to avoid received spectrum corruption issues caused by the lfm frequency u201c staircase u201d of the fractional n synthesizers fig2 1 and 2 2 show schematic block diagrams of an exemplary system 130 excluding an output device and a controller that performs dual mode pulse fmcw operation using lfm or nlfm the system 130 can produce signals in the s and x bands the s band is 2 9 3 1 ghz the x band is 9 2 to 9 5 ghz the system 130 can output signals to 13 ghz when the system 130 is commanded to operate in fmcw or lfm stretch compression modes a switch 154 allows a divided power and delayed signal associated with the signal outputted by a first synthesizer 160 based on a signal from a controller i e clock clk and or field programmable gate array fpga such as that produced by hittite microwave corporation to be sent to a mixer 140 the mixer 140 combines the divided and delayed signal with a processed return signal from an antenna 138 via a circulator 156 the return signal outputted by the circulator 156 is sent to a receiver protect device 172 which outputs to.