Selfmixing heterodyne system

摘要

High receiver sensitivity and narrowband coherent resolution can be achieved at millimeter and submillimeter wavelengths through the process of heterodyning or intermediate frequency (IF) generation. The two frequencies, whose IF is being generated, need not be very stable in frequency or phase themselves. The requirement is only, that they fluctuate identically in frequency and phase, so that their fluctuations cancel at the IF. This can be achieved by deriving both from one and the same source. We have applied this process twice in a millimeter and submillimeter receiver of high sensitivity and resolution. At the same time the receiver is very simple, since the frequency and phase stability of the two sources involved does not affect sensitivity and resolution.