The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 06, 1990
Filed:
Nov. 09, 1989
Stephen D Taylor, Agoura, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
A system is disclosed for measuring and correcting for waveform modulation errors in a radar system employing FM signals and a digitally controlled waveform generator. The system relies on the assumption that the transmitter and other waveform phase and amplitude error contributions are slowly varying with respect to the radar mode data collection time and that instantaneous pulse-by-pulse correction is not necessary. During a calibration mode, a small portion of the transmitter output is input into the receiver and mixed with the waveform generator signal, with the waveform modulation being removed from the mixer signal, such that the mixer signal is at a constant IF but with phase and amplitude variations that result from the distortions. The radar digital processor measures these distortions, and during normal radar operation predistorts the waveform generator signal with phase distortions in antiphase with the measured distortions to compensate for the measured distortions. Amplitude distortions are compensated by control of a variable attenuator device. As a result, the system compensates for the exciter and transmitter distortions as well as distortions introduced by the receiver input circuitry.