Patent ID: 8787863

Claim:
A method for shifting a frequency of a radio frequency (RF) signal in a selected direction, the method comprising: supplying an RF input signal to a first RF input switch from an RF input port; determining an ordered set of phase shift values to be applied to the RF input signal; determining a set of times each element of which corresponds to a time at which a phase shift value is to be applied to the RF signal; for each phase shift value within the ordered set of phase shift values: controlling the first RF input switch to select an input of a first phase shifting device and controlling a second RF input switch to select an input of a second phase shifting device, wherein the input of the first phase shifting device and the input of the second phase shifting device are selected to apply the phase shift value at its corresponding time to the RF input signal; and supplying the output of the first phase shifting device to the second phase shifting device via the second RF input switch; and supplying to an RF output port a frequency shifted signal from an output of the second phase shifting device.