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. 23, 1998
Filed:
Sep. 15, 1995
Applicant:
Inventors:
Masao Nagano, Saitama, JP;
Hitoshi Takahashi, Gyoda, JP;
Assignee:
Advantest Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B / ;
U.S. Cl.
CPC ...
455115 ; 455 671 ; 4552261 ; 375224 ;
Abstract
An FM input signal V(t) is A/D converted, then an in-phase component I and a quadrature component Q are obtained. Then, an instantaneous phase .theta.=tan.sup.-1 (Q/I) of the V(t) is obtained and also an instantaneous frequency of the modulated signal f.sub.a (t)=(1/2.pi.)d.theta./dt is obtained. Alternately, f.sub.a (t)=(IdQ/dt-QdI/dt)/{2.pi.(I.sup.2 +Q.sup.2)} is directly obtained from I and Q. A positive peak P+ and a negative peak P- of the obtained f.sub.a (t) is detected to display the average value of these as a frequency deviation.