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:
Apr. 09, 2002
Filed:
Dec. 21, 2000
William Eric Main, Mesa, AZ (US);
Danielle L. Coffing, Tempe, AZ (US);
Klaas Wortel, Phoenix, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A demodulator circuit ( ) includes an oscillator ( ) and an injection circuit ( ). An Automatic Frequency Control (AFC) signal adjusts the tail current of a current source ( ) provided in the oscillator ( ) and the tail current of a current source ( ) provided in the injection circuit ( ). A phase detector ( ) compares the phase of the signal generated by the oscillator ( ) with the phase of the injected input signal. The phase detector ( ) generates an output signal V having a value of zero when the input signal is in quadrature with the signal generated by the oscillator ( ), but generates a non-zero signal that is used to adjust the AFC signal when the input signal and the signal generated by the oscillator ( ) are not in quadrature.