公开(公告)号：JPH10209912A

公开(公告)日：1998-08-07

申请号：JP35721397

申请日：1997-12-25

Applicant: LUCENT TECHNOLOGIES INC

Inventor： YOSUN UU ,  R ANTHONY SHOVER

IPC: H04L27/22 ,  H03D1/22 ,  H03D3/00 ,  H04B1/59 ,  H04B5/00

Abstract: PROBLEM TO BE SOLVED: To ensure the appropriateness of an RFID (radio frequency identification) system by using a phase shifter which causes a 90-degree phase shift out of one of modulator output signals in regard to the 2nd frequency and an adder which adds another modulator output signal to a phase-shifted output signal in terms of vector. SOLUTION: An in-phase/quadrature phase coupler of an RFID system utilizes a modulation rear dispersion technique with which a modulated subcarrier undergoes the rear dispersion modulation for a CW carrier signal. Then the phase coupler connects together the quadrature and in-phase outputs of an quadrature demodulator in terms of non-destruction. The I and Q outputs of the quadrature demodulator are orthogonal to each other in relation to the carrier frequency. The I output is applied to the input side of a phase shifter 200 and causes a 90-degree phase shift to the I mixer output in relation to the subcarrier frequency. The output of the shifter 200 is connected to the input side of an adder 202. The output of the adder 202 is equal to the vector sum of the Q output and the phase-shifted I output.