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:
Feb. 28, 1995
Filed:
Jan. 08, 1993
Kyle L Bernard, Tigard, OR (US);
Tektronix, Inc., Wilsonville, OR (US);
Abstract
An in-service hum and low frequency distortion measurement technique for in-service cable television channels having a video modulated carrier frequency obtains peak samples of the horizontal sync signal to effectively filter out the vertical interval frequency. The data record formed by the peak samples is filtered and input to a fast Fourier transform to obtain magnitude values for the fundamental and first harmonic frequency components corresponding to a powerline. From these magnitude values hum and low frequency distortion is computed as a percentage relative to the amplitude of the carrier frequency. The same procedure may be used with an input CW signal in an out-of-service measurement for hum only, the difference between the in-service and out-of-service measurements determining the low frequency distortion due to the video signal.