ARRAY OF COUPLED PHASE-LOCKED OSCILLATORS AT 160 GHZ

A ten-channel millimeter-wave heterodyne phase measurement system is c urrently under construction. This system will be used for electron den sity measurement at the plasma experiment W7-AS. Main features are: 1) twofold usage of each 160-GHz oscillator to excite both the transmitt ing signal to the plasma and the local oscillator (LO) signal for down conversion and 2) the phase-locked loops (PLL's) of each oscillator ar e coupled in a chain. This letter describes the millimeter-wave part a nd the digital PLL circuits of that system. Test results of the first three channels, which are already running in the laboratory, are prese nted.