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:
May. 14, 1991
Filed:
Mar. 03, 1989
Applicant:
Inventor:
David L Hershberger, Nevada City, CA (US);
Assignee:
The Grass Valley Group, Inc., Nevada City, CA (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
375 62 ; 375118 ; 328 14 ;
Abstract
A low jitter direct digital frequency synthesized frequency shift keyed modulator has a tapped delay line to provide polyphase sampling of an asynchronous data input signal. The samples from the tapped delay line are input to a correction signal generator that produces a correction signal as a function of the location of data transitions in the data input signal with respect to a specified point of a sample clock pulse. The correction signal is used to offset a modulating input to a direct digital frequency synthesizer so that the frequency shift keyed output reflects the data transitions within 1/n of the period of the sample clock pulse.