US 11,674,993 B2
Measuring error in signal under test (SUT) using multiple channel measurement device
Steven D. Draving, Colorado Springs, CO (US)
Assigned to KEYSIGHT TECHNOLOGIES, INC., Santa Rosa, CA (US)
Filed by Keysight Technologies, Inc., Santa Rosa, CA (US)
Filed on Nov. 29, 2021, as Appl. No. 17/536,734.
Application 17/536,734 is a division of application No. 16/109,440, filed on Aug. 22, 2018, granted, now 11,255,893.
Prior Publication US 2022/0082603 A1, Mar. 17, 2022
Int. Cl. G01R 29/26 (2006.01); G01R 13/02 (2006.01); G01R 31/317 (2006.01)
CPC G01R 29/26 (2013.01) [G01R 13/0218 (2013.01); G01R 31/31709 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of measuring a characteristic of a signal under test (SUT) output by a device under test (DUT) using a signal measurement device having a plurality of input channels, the method comprising:
receiving the SUT;
digitizing a first copy of the SUT in a first input channel of the plurality of input channels to obtain first digitized waveforms;
digitizing a second copy of the SUT in a second input channel of the plurality of input channels to obtain second digitized waveforms;
repeatedly determining measurement values of the SUT characteristic in the first digitized waveforms to obtain a plurality of first measurement values;
repeatedly determining second measurement values of the SUT characteristic in the second digitized waveforms to obtain a plurality of second measurement values, each second measurement value being paired with a first measurement value, respectively, to obtain a plurality of measurement value pairs;
multiplying the first measurement value and the second measurement value in each of the measurement value pairs to obtain a plurality of measurement products;
determining an average value of the measurement products to obtain a mean-squared value (MSV) of the measured SUT characteristic; and
determining a square root of the MSV to obtain a root-mean-squared (RMS) value of the measured SUT characteristic,
wherein the RMS value of the measured SUT characteristic includes variations in the SUT that are in both the first and second input channels, and substantially omits variations not in the SUT, which are introduced by only one of the first input channel or the second input channel as a result of respective measurement errors.