5.8 GHz One Antenna Reflective Tag
CHR2244-QDG
Application Information
General Transmission system
The transmission system is described as following, the tag doesn’t generate any frequency:
Fo
F-AM
BEACON
TAG
DOWNLINK
figure 1a
TRANSMIT
MODE
RECEIVE
MODE
Fo
BEACON
UPLINK
figure 1b
TAG
RECEIVE
MODE
TRANSMIT
MODE
Fo
Fm
Figure 1: Transmission system operating principle
Two modes of communication are implemented
From beacon to tag (figure 1a): the beacon is in transmit mode while the tag is in the receive mode.
The beacon sends an Amplitude Modulated (AM) RF signal to the tag. In figure 1a, F-AM is the
amplitude modulation frequency and F0 is the carrier.
From tag to beacon (figure 1b): the beacon is in receive mode while the tag is in transmit mode. The
beacon sends a continuous wave (CW) RF signal to the tag, this signal is then mixed (at tag level) with
the MOD input signal (Fm) thanks to a reflective mixer. The reflected signal is sent back to the beacon
and is demodulated thanks to an homodyne receiver.
Ref. : DSCHR2244-QDG9030 - 30 Jan 09
10/14
Specifications subject to change without notice
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Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09
UMS [ UNITED MONOLITHIC SEMICONDUCTORS ]
