In this memo, we present measured receiver noise data of a 200-300 GHz SIS mixer driven by a pre-prototype of the YIG-tunable LO driver followed by a varistor tripler. After identifying and solving some signal-to-noise problems in the LO driver chain, measurements were taken from 220-270 GHz showing an average noise over a 4-12 GHz IF less than 5 K for the worst LO frequency over the identical mixer and varistor tripler being driven by a W-band Gunn oscillator. The average excess noise over all measured LO frequencies is 1.4 K. The optimum LO driver for which these measurements were taken includes a YIG-tuned filter (YTF). LO driver configuration options without the YTF are explored with encouraging initial results.
View a pdf version of ALMA Memo #436.
Last modified: 2002-10-08
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