CHR2244 Datasheet, PDF (11/16 Pages) United Monolithic Semiconductors – 5.8 GHz One Antenna Reflective Transponder for Tag GaAs Monolithic Microwave IC

5.8 GHz One Antenna Reflective Tag
CHR2244
Application Information
General Transmission system
The transmission system is described as follows, the tag doesn’t generate any frequency :
DOWNLINK ^BEACON
figure 1a
TRANSMIT
MODE
Fo
F-AM
TAG
RECEIVE
MODE
UPLINK
figure 1b
Fo
BEACON
RECEIVE
MODE
TAG
Fo
Fm
TRANSMIT
MODE
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. : DSCHR2244QDG5053 - 22 Feb 05
11/16
Specifications subject to change without notice
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