Patent ID: 6313619
Filing Date: 2001-11-06
Classification: G01R

Abstract:
Arrangement for the measurement of phase noise of an output signal of a test specimen (28) using a spectrum analyzer whose measuring branch comprises a plurality of serially connected heterodyne stages, each having a respective mixer (3, 6, 9), a mixing oscillator (4, 7, 10), and an intermediate frequency filter (5, 8, 11),wherein a compensation generator is comprised of a plurality of serially connected heterodyne stages (10, 18, 19; 7, 15, 16; 4, 12a, 13) arranged in reverse order to the heterodyne stages of the measuring branch, and having an input oscillator (21) which corresponds to a last intermediate frequency of the measuring branch said heterodyne stages (10, 18, 19; 7, 15, 16; 4, 12a, 13) of said compensation generator each comprising a respective mixer (13, 16, 19) and an intermediate frequency filter (12a, 15, 18), with said mixers (13, 16, 19) of the compensation generator being respectively supplied by said mixing oscillators (4, 7, 10) of said measuring branch, andwherein an output signal of said compensation generator is added to the output signal of the test specimen (28), with an approximately equal value level and being approximately oppositely phased thereto, in an adder stage (27) serially connected to an input (1) of the measuring branch.