公开(公告)号：CA2138029C

公开(公告)日：1998-09-22

申请号：CA2138029

申请日：1994-05-04

Applicant: MOTOROLA INC

Inventor： SCHWENT DALE GERARD ,  OSMANI RASHID MASHID MASOOD

IPC: H01P5/04 ,  H01P5/12 ,  H01P5/18 ,  H04B1/04

Abstract: (see fig.1) An apparatus and method for varying coupling of a radio frequency (RF) signal (4 08). This is advantageously used for increasing the dynamic range of a power detector (406;) in an automatic power level control loo p (403) of a transmission unit (404), while maintaining unit efficiency at higher power levels. This is accomplished by selecting betwee n a first operating mode of the RF coupler (405) having strong coupling, responsive to a first predetermined power level, s uch that the RF coupler (405) produces a first coupled RF signal (509) responsive to the RF signal (408) and a second operating mode of th e RF coupler (405) having weak coupling, responsive to a second predetermined power level, such that the RF coupler (405) produces a seco nd coupled RF signal (510) responsive to the RF signal (408).