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. 31, 1991
Filed:
Dec. 18, 1990
Yoshio Takeuchi, Tokyo, JP;
Teruhiko Honda, Tokyo, JP;
Kokusai Denshin Denwa Co., Ltd., Tokyo, JP;
Abstract
A PSK signal which is subject to frequency fluctuation and noise is demodulated through a quasi-coherent detection process with a fixed local frequency oscillator (5) noise elimination process using a low pass filter (17,18) after frequency adjustment, and a frequency and phase regeneration process using a PLL circuit (20). The PLL circuit (20) is updated by the estimated center frequency of a received signal by using an FFT (fast Fourier transform) circuit (11), a power spectrum means (12,13,14), and a frequency estimation circuit (15) estimating the center frequency based upon the fact that the modulated signal component exists only on a high level portion of the frequency spectrum.