ELECTRONICALLY TUNABLE PARAMETRIC UPCONVERTER.

A cryogenically-cooled, parametric up-converter has been developed that will operate in the 4-8 GHz band and exhibits the following performance at a typical operating frequency Frequency, 6.2 GHz instantaneous bandwidth, 50 MHz gain, 20 db noise temperature, 20 K at 30 K ambient temperate and tuning range with a minimum of 10 db gain, 1 GHz. The up-converter tuning range is determined by the signal circuit bandwidth under pumped conditions. An increase in tuning range without a decrease in gain can be achieved by increasing the diode cut-off frequency or by the use of a multi-tuned signal circuit. With a single-tuned signal circuit and presently available diodes, the maximum tuning range for a minimum gain of 10 db is about 1 GHz. However, if the idler circuit of an up-converter is terminated in a negative resistance, octave-band tuning can be achieved without sacrificing gain or noise performance. Author