Blackbody heterodyne receiver for NEP measurements and wideband photodetector characterization.
A blackbody radiometer is designed to measure the noise equivalent power of 10.6-microm heterodyne-receiver front ends as a function of intermediate frequency from 100 to 6000 MHz. The system includes noise diode injection and IF response normalization, making it particularly useful for characterizing high-speed photo-detectors coupled to wideband preamplifiers. Experimental results for some 77-K HgCdTe photodiodes indicate amplifier-limited NEP values <2 x 10(-19) W/Hz at 4.0 GHz. The NEP data agree well with those obtained by the standard blackbody heterodyne technique.
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Hughes Aircraft Company, Space & Communications Group, PO Box 92919, Airport Station, Los Angeles, California 90009, USA.