Patent ID: 6963624

Claim:
An apparatus for converting a radio frequency (RF) signal and its reference signal comprising a signal source for providing a signal with a predetermined frequency; a first multiplier for combining a signal responsive to the RF signal and another signal responsive to the signal generated by the signal source, and providing at least one output signal; a second multiplier for combining a signal responsive to the reference signal and another signal responsive to the output signal from the first multiplier, and providing an output signal; a first 90 degree phase shifter for receiving a signal responsive to the reference signal, and generating an output signal; a third multiplier for combining a signal responsive to the output signal from the first multiplier and a signal responsive to the output signal from the fire 90 degree phase shifter, and providing an output signal; a second 90 degree phase shifter for receiving a signal responsive to a signal selected from the group consisting of the output signal from the second multiplier and the output signal from the third multiplier, and providing an output signal; and an adder for combining a signal responsive to the output signal from the second multiplier and another signal responsive to the output signal from the third multiplier, and providing a new signal.