US 12,345,748 B2
Removing test equipment intermodulation interference and noise from power spectral density measurements
Chen Cao, Shanghai (CN); Christian Volf Olgaard, Saratoga, CA (US); Ruizu Wang, Santa Clara, CA (US); and Qingjie Lu, Shanghai (CN)
Assigned to LitePoint Corporation, San Jose, CA (US)
Filed by LitePoint Corporation, San Jose, CA (US)
Filed on May 5, 2023, as Appl. No. 18/143,886.
Claims priority of application No. 202310462931.2 (CN), filed on Apr. 26, 2023.
Prior Publication US 2024/0361367 A1, Oct. 31, 2024
Int. Cl. G01R 23/18 (2006.01); G01R 27/30 (2006.01); G01R 29/26 (2006.01)
CPC G01R 23/18 (2013.01) [G01R 27/30 (2013.01); G01R 29/26 (2013.01)] 24 Claims
OG exemplary drawing
 
1. A method comprising the following operations:
(i) receiving a device signal from a device under test (DUT);
(ii) setting an attenuation value;
(iii) applying the attenuation value to attenuate the device signal for input to a frequency spectrum analyzing device, the frequency spectrum analyzing device producing a noise signal and intermodulation interference that are added to the device signal;
(iv) obtaining a power spectral density value, where the power spectral density value comprises a power, at a frequency value, of a combined signal that is based on the device signal, the noise signal, and the intermodulation interference;
(v) repeating operations (ii), (iii), and (iv) one or more times to produce multiple power spectral density values;
(vi) repeating operations (i), (ii), (iii), (iv), and (v) one or more times to add power spectral density values to the multiple power spectral density values; and
(vii) obtaining a power spectral density of the device signal having at least some of the intermodulation interference from the frequency spectrum analyzing device removed by performing an optimization process that is based on the multiple power spectral density values.