CHR2244

5.8 GHz One Antenna Reflective Tag

Ref. : DSCHR2244QDG5053 - 22 Feb 05

12/16

Specifications subject to change without notice

Route Départementale 128 , B.P.46 - 91401 ORSAY Cedex - FRANCE

Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09

Tag operating modes

Within this transmission system, The CHR2244 operates in three basic modes depending on the WK_in

and T/R input signal levels. They are described hereafter :

1 - The STANDBY MODE (figure 2) is a very low power consumption state. In this mode an

Amplitude Modulated RF signal is necessary to produce a DC voltage at the SB_out output which may be

used to wake-up the CHR2244 by applying Vcc to the WK_in input.

Det

T/R

0V or HI

MOD

0V or HI

WK_in

0V or HI

DATA_out

RF in

AM

modulated

SB_out

to controller

Data from controller

RF-in

AM

modulated

TR

0V

WKIN

0V

SB_out

Vcc

Figure 2a : Standby mode

The received AM modulated RF spectrum is the following, versus the modulation index (m). This

plot is done for the minimum AM modulated RF input power ( -40 dBm ) and only for an ideal spectrum

with only 2 rows ( 5.7995 and 5.8005 GHz ) i.e. the 5.8 GHz carrier AM modulated with a 500 kHz signal.

7dB

9dB

12dB

5.8005GHz

5.7995GHz

5.8GHz

m=0.5

5.8GHz

5.8GHz

-40dBm

m=0.7

m=0.9

5.8005GHz

5.7995GHz

5.8005GHz

5.7995GHz

Figure 2b : AM modulated RF spectrum

IF 500kHz

RF

5,8GHz

MODULATOR

ATTENUATOR

CHR2244

+V

OSCILLOSCOPE

SB_OUT

Figure 2c : Standby test bench diagram