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:
Jun. 21, 1994
Filed:
Jun. 18, 1993
Applicant:
Inventors:
Gerhard Greving, Untergruppenbach, DE;
Werner Poschadel, Kornwestheim, DE;
Assignee:
Alcatel Sel Aktiengesellschaft, Stuttgart, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01S / ; G01S / ;
U.S. Cl.
CPC ...
342413 ;
Abstract
Two-frequency transmitting apparatus (S1, S2, LA) for instrument-landing systems is insensitive to so-called difference in depth of modulation (DDM) distortions caused by reflections of a clearance signal from obstacles (H) located near the runway (RW). This insensitivity is achieved by providing different phase shifts to the equal modulation frequencies (90 Hz and 150 Hz) used for the course and clearance signals. The different phase shifts correspond to a phase shift of a common fundamental frequency (30 Hz). The two-frequency transmitting apparatus can be used to specify a localizer course or a glide path.