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. 29, 1992
Filed:
Aug. 26, 1991
Stephen P Caldwell, Columbia, MD (US);
Thomas D Merrell, Jr, Columbia, MD (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A linear FM waveform generator employs direct digital synthesis and includes a digital linear FM signal generator, a digital-analog converter, and a sampler means. The linear FM waveform generator includes a frequency slope register coupled to a first stage integrator which in turn is coupled to a second stage integrator, all of which operate off a system clock. The output signal from the second stage integrator represents phase as a quadratic function of time. A stored sine look-up table is referenced to generate an output digital signal representing amplitude as a function of time. The output digital signal is converted to an analog linear FM waveform which in turn is coupled to a sampler that includes a step recovery diode and a fast switch. The sampler aperture is sufficiently small that the sampler output linear FM waveform includes base and higher harmonic spectra with amplitude attenuation small enough to enable a third or higher harmonic spectra to be used for generation of the output linear FM waveform. The sampler output is filtered to pass a higher harmonic spectra which is directly coupled to output multiplication and filter circuitry.