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.

Date of Patent:
Feb. 01, 2000

Filed:

Dec. 30, 1996
Applicant:
Inventor:

Jae-Sun Park, Ahnsan, KR;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
375344 ; 375327 ; 375376 ; 455 75 ;
Abstract

A digital radio communication system includes a first down converter for converting down a predetermined radio frequency (RF) signal into a first intermediate frequency (IF) signal according to a first local oscillation signal; a second down converter for converting down the first IF signal into a second IF signal according to a second local oscillation signal; a demodulator for demodulating the second IF signal according to a third local oscillation signal and outputting a predetermined base band of a signal; a modulator for modulating the predetermined base band of signal according to the second local oscillation signal and outputting a third IF signal; a up converter for converting the third IF signal to a RF signal according to the first local oscillation signal; a first phase-locked loop (PLL) for controlling the first local oscillation signal in a direction where the sum of the frequency deviation between the first local oscillation signal and a reference frequency signal and the frequency deviation between the second local oscillation signal and the reference frequency signal is removed; and a second PLL for controlling the third local oscillation signal in a direction where the frequency deviation between the third local oscillation signal and the reference frequency signal is removed.


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