Multichannel Phase Noise Measurement System.
Patent, filed 21 Apr 86, patented 31 May 88,
DEPARTMENT OF THE AIR FORCE WASHINGTON DC
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A multichannel phase noise measuring system is disclosed which is capable of measuring the phase noise of two signal source operating between 100 MHz and 24 GHz. This system has two input channels and a mixer which produces a difference frequency between the signals received in the input channels. The difference frequency containing the phase noise is frequency multiplied and amplified to raise the phase noise level 12 dB. The multiplied and amplified difference signal is phase locked to a commercially available frequency synthesizer with inferior noise characteristics to the units being tested. By amplifying the phase noise of the original signals above the phase noise levels of the commercially available frequency synthesizer, they become measurable. Patents. rh