A homodyne radar system includes a mixer that outputs a signal having a mixer output frequency that is a frequency difference between two input signals. When the frequency difference is small, low frequency noise may mask the actual signal. A variable phase shifter is added to one of the mixer inputs to change the phase at a predetermined rate of change. The phase shifter shifts the frequency of the input signal so that the mixer output frequency is offset by the predetermined rate. The low frequencies are mapped to frequencies that are above the noise frequencies. The phase shift may be achieved by adding a constant phase at predetermined time intervals. The sampling frequency for the resulting signal may need to be increased to accommodate the higher frequencies.