Patent ID: 6184826
Filing Date: 2001-02-06
Classification: H01Q,H04B

Abstract:
A method for extending the dynamic range of a process for testing one or more characteristics of an antenna, wherein a spread spectrum carrier is emitted as a test signal from a test signal source and is incident upon said antenna, and a replica of a spreading sequence of said spread spectrum test signal is correlated with a signal demodulated from energy received at said antenna, so as to extract energy in said test signal and exclude energy in unwanted signals that may be incident upon said antenna, said extracted test signal energy being processed to derive a measure of said one or more characteristics of said antenna, said method comprising the steps of:(a) coupling said carrier signal through successive ones of a cascaded arrangement of a plurality of N mixer stages;(b) applying, to said successive ones of said plurality of N mixer stages, respectively different, relatively low rate, PN spreading sequences, that are mutually offset in time by a fraction of a chip, thereby producing, at an output of an Nth mixer stage of said plurality of N mixer stages, a direct sequence spread spectrum carrier having its energy spread out over a bandwidth that is N times the spreading bandwidth of an individual one of said PN spreading sequences; and(c) emitting the spread spectrum carrier produced in step (b) as said test signal from said test signal source.