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:
Dec. 13, 1988
Filed:
Jan. 21, 1988
Applicant:
Inventor:
Richard M Waltham, London, GB;
Assignee:
Thorn EMI plc, London, GB;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03K / ; H03K / ; G05F / ;
U.S. Cl.
CPC ...
328155 ; 328156 ; 328157 ; 328133 ; 328134 ; 307511 ; 307525 ; 307529 ;
Abstract
A digital phase-locked loop using a binary overflowing accumulator as a numerically controlled oscillator has external compensation to eliminate frequency-dependent phase offset problems while not requiring any second-order filtering. Operation of the NCO adder initiates with value set by the center frequency control and under the latching action of the latch clocked by the reference oscillator produces a linearly stepped output. Detection of the most-significant bit values produces a square wave at the output. The phase detector latch is used for phase correction, while comparator eliminates steady-state phase error.