公开(公告)号：FR2759827B1

公开(公告)日：2001-05-25

申请号：FR9801198

申请日：1998-02-03

Applicant: MOTOROLA INC

Inventor： VLAHOS CONSTANTINIE ,  PECKHAM DAVID S ,  SKUTTA FRANK ROBERT

IPC: H04B1/40 ,  H03D7/12 ,  H03J1/00 ,  H04B1/26 ,  H04B1/44 ,  H04B1/16

Abstract: A method and apparatus enables a communication device (100) to operate in multiple bands, such as GSM 900 MHz, DCS 1800 MHz, and DCS 1900 MHz bands, by eliminating the need for a mixer for each band. In a dual band GSM/DCS 1800 radiotelephone, for example, the local oscillator (LO) injection frequencies for both GSM and DCS bands are provided to a mixer (234) through the use of combination filters (222, 246). Thus, the duplexing and matching requirements to the mixer input are simplified and the signal losses are minimized. The common output ports of the GSM RX/LO combination filter and DCS RX/LO combination filter are duplexed to the input of the mixer. Also, the input impedance matching of the mixer is designed to match the impedance for the received signals in each band, as well as provide an RF trap at the IF frequency. The match at the output of the mixer is designed to match the impedance of the IF filter and provides a low impedance to RF input frequencies. Finally, a tri-band radiotelephone is also described.

公开(公告)号：FR2759827A1

公开(公告)日：1998-08-21

申请号：FR9801198

申请日：1998-02-03

Applicant: MOTOROLA INC

Inventor： VLAHOS CONSTANTINIE ,  PECKHAM DAVID S ,  SKUTTA FRANK ROBERT

IPC: H04B1/40 ,  H03D7/12 ,  H03J1/00 ,  H04B1/26 ,  H04B1/44 ,  H04B1/16

Abstract: A method and apparatus enables a communication device (100) to operate in multiple bands, such as GSM 900 MHz, DCS 1800 MHz, and DCS 1900 MHz bands, by eliminating the need for a mixer for each band. In a dual band GSM/DCS 1800 radiotelephone, for example, the local oscillator (LO) injection frequencies for both GSM and DCS bands are provided to a mixer (234) through the use of combination filters (222, 246). Thus, the duplexing and matching requirements to the mixer input are simplified and the signal losses are minimized. The common output ports of the GSM RX/LO combination filter and DCS RX/LO combination filter are duplexed to the input of the mixer. Also, the input impedance matching of the mixer is designed to match the impedance for the received signals in each band, as well as provide an RF trap at the IF frequency. The match at the output of the mixer is designed to match the impedance of the IF filter and provides a low impedance to RF input frequencies. Finally, a tri-band radiotelephone is also described.