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:
Sep. 13, 1994
Filed:
Feb. 17, 1993
Alan R Bloom, Santa Rosa, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An analog ramp signal is used to control the frequency of a swept radio-frequency (RF) test oscillator. The analog ramp signal is generated by applying a fixed reference voltage to an analog integrator circuit. However, ramp accuracy is degraded by integrator gain error, drift, and nonlinearity. To correct for these errors, the analog ramp signal is periodically compared to a digital ramp signal generated by a digital-to-analog converter (DAC) during the course of a sweep. Preferably, the analog ramp signal is compared to the digital ramp signal many times during the course of the sweep. The difference between the two ramp signals is scaled and combined with the reference voltage to correct the slope of the analog ramp signal. An additional DAC preferably adjusts the gain of the feedback loop.