Local-oscillator noise cancellation in the subharmonically pumped down-converter

The noise power at the IF output of a superheterodyne mixer which is caused by local-oscillator noise can be significantly reduced by using the recently developed subharmonically pumped down-converter. In many cases this reduction is so large that even noisy sources, such as IMPATT oscillators, can be used to pump low-noise mixers without causing significant degradation of noise figure.